Method for Installation of Cable Tray-(PART 2)


  • Horizon Tee Support: NEMA Standard
  • Supports for horizontal tee fittings should be located at a distance, no greater than 610 mm (24″) from each end of the fitting on the attached ladder. Fitting should also be supported once on each side rail. For 305 mm (12″) radius tees, place supports no greater than 610 mm (24″) from each end of the fitting on the attached ladder.

1

  • Horizon Cross Support: NEMA Standard
  • Supports for horizontal cross fittings should be located at a distance, no greater than 610 mm (24″) from each end of the fitting on the attached ladder.
  • Fitting should also be supported once on each side rail. For 305 mm (12″) radius cross, place supports no greater than 610 mm (24″) from each end of the fitting on the attached ladder.

2

  • Reducer Support: NEMA Standard
  • Place horizontal supports (2) at a distance no greater than 610 mm (24″) from each end.

3

  • Horizontal Y Support: NEMA Standard
  • Place horizontal supports at a distance no greater than 610 mm (24″) from each of the three openings and at the midpoint of the fitting at 22.5°

 4

  • Vertical Inside / Outside Support: NEMA Standard
  • Vertical cable tray elbows at the top of runs should be supported at each end. At the bottom of runs, they should be supported at the top of the elbow and within 610 mm (24″) of the lower extremity of the elbows. Both Inside and Outside Fittings should be additionally supported at a distance no greater than (24″) from each end.

5

  • Offset Reducing Connection & Tray to Box / Floor Connection:

6

(IV) Cable Tray Installation:

  • Ensure that the Cable Tray’s, dimension, elevation and other fittings are properly leveled and that they are coordinated to the other services fixtures.
  • The width of Cable Tray/trunking/ladder should have sufficient width to take the cable without crowding and shall allow for future 25% space. The cables should not be stacked together.
  • If the conductors carried by trays or ladders are of various systems, the ELV and data processing or different insulation, the cable ladder or trays should be separate. Use insulating barriers where it is necessary. However, approval from the engineer is required.
  • Earth continuity shall be ensured throughout the length of the Trays and Trunking
  • Cable Tray Installation on Roof / Floor:
  • Cable tray should not be laid directly on the floor or roof.
  • Cable trays installed on roof shall be supported using Gl brackets or concrete blocks.
  • It should be mounted far enough off the floor or roof to allow drainage of water.
  • The cables to exit through the bottom of the cable tray.
  • Where cable trays are installed in roof or exposed to sunlight, factory made cover shall be fixed to protect the cables from direct sunlight.
  • Cable Trunking runs shall be arranged so that the lid is always on top or side. Lid shall be fixed to the trunking using factory made quick fix type clips.
  • Open ends of the trays / trunkings shall be capped with purpose made end caps.
  • Cable Tray Accessories:
  • Where cutting of the trays is needed, circular saws will be used. Cable tray cut edges will be rasped or welded if it is necessary, galvanized points will be cleaned then it will be sprayed with galvanizing spray immediately.
  • Cut portion of Trays and Trunking, shall be made free of sharp edges by filing and coated with zinc rich and top coat and jointed using fish-plates with bolts and nuts.
  • Any cutting on the cable tray to be done along the solid area and not across the perforation of the cable tray. Burrs needs to be removed and cuts need to be protected with anti-rust galvanized paint to prevent rust.
  • The minimum radius of Cable Tray should equal the minimum bending radius of the cables. Depending on the number of cables to be placed in the system it may be advantageous to use the next highest radius.
  • Installation of splice connectors
  • Splice connectors shall be located as recommended by the manufacturers.
  • Splice joints should be designed and placed so as to maximize the rigidity of the cable tray.
  • Splice connectors shall be attached by round / Hexa head bolts with the nuts and washers located on the outside of the tray or ladder unless otherwise specified by the manufacturer.
  • Thermal expansion splices shall be installed wherever expansion joints occur.

7

  • All straight joints, bends and offset connections shall be made neatly using standard fittings (fish plate and coupler). Only when these are inappropriate, fabricated bends/offsets shall be used.

(5) Cleaning of Work Area:.

  • There should be a visual inspection of the trunking from inside side after installation. This is to be sure that it is free from Debris, burrs and waste materials.
  • There are no sharp edges that could cause damage to the cables during installment.
  • Galvanized coating damaged by excessively rough treatment during transit and erection shall be repaired using at least two coats of good quality zinc-rich paint complying with BS 4652.
  • Upon completion of installation of cable trays/trunking in one area, the completed work shall be presented for Inspection and shall be protected by providing polyethylene sheet cover.

(6) Codes and Standards:.

  • IS 4759: Hot-dip zinc coatings on structural steel and other allied products 
  • IS 2629: Recommended Practice for Hot-Dip Galvanizing of Iron and Steel
  • IS 2633: Methods for testing uniformity of coating of zinc coated articles
  • IEC 61537 Cable Management- Cable Tray System and Cable Ladder System
  • BS 4652 Specification for zinc-rich priming paint
  • National Electrical Manufacturers Association (NEMA) Standard

8

Method for Installation of Cable Tray-(PART 1)


(1) Purpose:

This method explains the Procedures or sequence of activity for safely installation and Testing of cable tray, and it’s accessories as per the standard Practice and Code.

(2) General Equipment & Tools: . 

  • The equipment that will be engaged for Installation of Cable Tray will be
  • Tool Box with Screwdriver, Pliers, Spanner , Hammer
  • Drilling Machine with various Bits , Grinding & Cutting Machine
  • Electrical Tester , Continuity Tester ,Multi Meter
  • Cutter , Blower
  • Knockout punch and Flat File
  • Galvanizing paint
  • Marker, Measuring tape, Level gauge / Spirit level.
  • Ladder / Scaffolding / Mobile scaffold
  • Chain Block and Pipe Wrench
  • Portable Lights
  • Removable Barricades

(3) Storage & Material Handling: .

  • The storage area must be free from dust and Water leakages / seepages.
  • Manufacturer recommendation shall always be followed in loading/unloading and storing of Material.
  • Material and its accessories shall be unloaded handle with care in designated area of the Store (Do not directly drop to Ground) to avoid any damages.
  • Materials shall be stored in a dry place which is free from water or from weather effects and protection should be given to the material by means of covering the material with Tarpaulin sheet.
  • The Material will be stacked / unload in the site store on a proper stand on wooden loft on a flat surface at a sufficient height from Ground.
  • If Material are dispatch in packs or pallets, each pack or pallet shall be lifted individually with suitable lifting equipment.
  • The material shall be transported / Shifted in their original packing to Site location.
  • The Material should be visually inspected for damage, which may have occurred during transport.
  • When bringing down materials, they should be handled with care and lowered carefully to the ground. They should not be dropped.

  • To prevent damage to cable tray, never pull cable tray from a truck trailer by chaining to the bottom rung and dragging cable tray out of the trailer

  • If the Material is found defective it shall not be installed and the cable shall be returned to the supplier for replacement.
  • Cable Tray and its accessories (pre-galvanized, hot dipped galvanized) shall be stored in a dry place, fully enclosed / ventilated store.

(4) Inspection of Materials:

  • Check The Material according to its Type, Size, Make
  • Visual inspection:
  • Type of Cable Tray
  • Type of Cable Tray Material
  • Type of Cable Tray Coating
  • Standard width of Cable Tray
  • Standard length of Cable tray
  • Cable Tray thickness
  • Flange height of Cable Trays
  • Proper painting / Galvanization and identification numbers of the cable trays
  • Physical Damages Inspection:
  • Damage on trays and ladders
  • Damage on galvanizing
  • Fittings and accessories are of proprietary type
  • Testing of galvanizing:
  • Uniformity of coating Thickness Test
  • Electrical continuity of connection
  • TRs not more than five year old from date of purchase order shall be reviewed for acceptance. Otherwise test shall be carried out.

BS EN ISO 1461

Table-1 Control Sample Size Related to Lot Size

Number of Lot

Min. Sample

1 To 3

All

4 To 500

3

501 To 1200

5

1021 To 3200

8

3201 To 10000

13

>10000

20

Inspection Lot: Single Order or Single Delivery Order

 

ISO 1461:2009 TABLE-3

Minimum coating thickness and mass on samples that are not centrifuged

Article and its thickness

Local coating thickness (minimum)µm

Local coating
mass
(minimum)g/m2

Mean coating thickness (minimum)µm

Mean coating
mass
(minimum)g/m2

Steel > 6 mm

70

505

85

610

Steel > 3 mm to < 6 mm

55

395

70

505

Steel > 1.5 mm to < 3 mm

45

325

55

395

Steel < 1.5 mm

35

250

45

325

Casting > 6 mm

70

505

80

575

Castings < 6 mm

60

430

70

505

NOTE This table is for general use: individual product standards may include different requirements including different categories of thickness. Local coating mass and mean coating mass requirements are set out in this table for reference in such cases of dispute.

(5) Sequence of Cable Tray Installation Works:

(A) Installation of Cable Tray:

(i) Shifting of Cable Tray on Site

  • Cable Tray shall be carefully unloaded or shifted to the site by using Crane/Hydra or by sufficient manpower and moved to a defined installation location.
  • Remove the packing and ensure that the Cable Tray is free from transportation damages
  • Check and ensure that approved drawings, the correct size and type of cable trays, trunking & accessories are ready for installation.
  • Ensure that cable trays/trunking and accessories received from site store for the installation are free of rusty parts and damages.

 (ii) Marking the Route:

  • Mark the route of Cable Tray and Trunking as per approved drawings with marking threads. The route of Cable Tray and Trunking need to be coordinated with other services and shall be confirmed by the Site Engineer.
  • Minimum space from the building structure and other services to be maintained (200 mm from the nearest point) to facilitate easy handling and maintenance of cables.
  • If Possible, Do not install Cable trays below water/sewage pipes.

(iii) Hanging Support:

  • The location of hangers and supports should be carefully marked as per the approved specifications and Drawings.
  • Required sizes of holes should be marked and drilled by using a drilling machine.
  • The threaded rod (M12 steel) or Specified rod should be fixed carefully into the anchor using clamping tools for a balance smooth twist. The threaded rod should be necessary thickness and length. Sizes should be as approved in the drawing. It should be done in such a way as to avoid damage to the threaded rod.
  • When thread is done, a washer should be inserted into it. The washer should also be the required size and of quality. It should be fixed properly and the nut fastened tight to ensure that the threaded rod is strong and able to bare load.
  • Trays and ladders shall be securely anchored to supports. They shall be secured such that the tray or ladder system will not move during cable installation.
  • Ensure that rod is properly vertical under operating conditions.
  • Tighten hanger load nut securely to ensure proper hanger performance. Tighten upper nut after adjustment
  • The distance between supports is called SPAN. The support span should not be greater than the length of the tray. This will prevent two connecting points from being located within one support span.
  • The support span should not be greater than the straight section length, or as recommended by the manufacturer, to ensure that no more than one splice is located between supports.

  • Cable Tray and Trunking joints are to be positioned as close to the supports as possible, not more than 300 mm from either side.
  • Splice joints fall between the support and the quarter point. When installing a 12-foot long section, for example, a support spacing of 3.7 m (12 foot) causes the splice joints to fall at the same position every time.

  • The maximum tray overhang past the last support should not exceed 600 mm (2 ft).
  • At every maximum of 1200 mm horizontally and 1500 vertically supports should be installed.
  • Horizontal cable trays and ladders shall be supported by either wall mounted support bracket or a hanger rod system. The intervals between supports shall be as recommended by the manufacturer but this shall not exceed 1 meter for wall mounted support brackets, and 2 meter for the hanger rod system.
  • The hanger, hanging support, cable tray bracket and the ladder should be trimmed to required size and galvanizing paint should be applied on the edges.
  • Group parallel runs of trunking should be supported together where it is possible.

  • For shaft cable trays and ladders that are vertical, all supports and fixings should be done as approved.
  • Do not cut or drill structural building members (e.g., I-beams) without approval by the Main contractor.
  • Warning: Do not use a cable tray as a walkway, ladder, or support for people; cable tray is a mechanical support system for cables and raceways. Using cable trays as walkways can cause personal injury and can damage cable tray and installed cables.
  • Horizon Fitting Support: NEMA Standard
  • Supports for horizontal fittings should be located at a distance, no greater than 610 mm (24″) from each end of the fitting on the attached ladder.
  • Fitting must also be supported at the radius center point on both sides of the fitting as per below:
  • At the midpoint (45°) of the arc for a 90° elbow.
  • At the midpoint (30°) of the arc for a 60° elbow.
  • At the midpoint (22.5°) of the arc for a 45° elbow, excluded are 305 mm (12″) radius fittings.
  • At the midpoint (15°) of the arc for a 30° elbow, excluded are 305 mm (12″) radius fittings.

Method for Installation of HVAC System (Part-4)


HVAC Refrigerant  Pipe Testing:

(A) Refrigerant Piping (Leak Check) by Pressure Testing:

  •  Pressure testing helps ensure a leak free system, a critical component to a successful installation.
  • Max PSI and duration of pressure tests can vary between manufacturers and should be reviewed in the installation manual.
  • All VRV systems should be pressure tested to 550 PSIG and held for 24 hours.
  • Pressure testing process: Tighten down stop valves before any pressure testing to prevent nitrogen
  • From leaking back through condenser and contaminating refrigerant.
  • Pressure testing shall be done in three (3) steps.
  • Step 1 – Leak check 3 minutes at 150 PSI
  • Step 2 – Leak check after 5 minutes at 325 PSI
  • Step 3 – Leak check after 24 hours at 550 PSI (450 psi for systems with vertical Air Handlers)
  • After the gauge reading reaches 550 psig, isolate the system by first closing the gauge manifold, then close the nitrogen cylinder valve.
  • Check the flared and brazed connec­tions for leaks by applying a bubble solution to all joints.
  • The bubble solution must be a solution designed for refrigerant leak testing. Common soap solution must never be used on refrigerant piping as those contain chemicals that could corrode copper and brass, and cause product malfunction.
  • If the pressure does NOT drop for 24 hours, the system passes the test.
  • In this case, the pressure drop of 9.5 psig was due to temperature differences, therefore, there is no leak in the refrigerant piping system.
  • If the pressure drops and it is not due to ambient conditions, there is a leak and it must be found. Remove the bubble solution with a clean cloth, repair the leak(s), and perform the leak / pressure check again.
  • After the system has been thoroughly tested and no leaks are found, depressurize by loosening the charging hose connector at the nitro­gen cylinder regulator. When system pressure returns to normal, completely disconnect the charging hose from the cylinder, and release the nitrogen charge from all refrigerant piping. Wipe off any remaining bubble solution with a clean cloth.
  • Ambient Conditions and the Leak / Pressure Check
  • If the ambient temperature changed between the times when pressure was applied and when the pressure drop was checked, adjust results by factoring in approximately 0.79 psi for each 1°F / 1°C of temperature difference.
  • Correction formula: (°F / °C Temperature when pressure was applied – °F / °C Temperature when pressure drop was checked) x 0.79.
  • Example: When pressure (550 psig) was applied, temperature was 80°F / °C; 24 hours later when pressure drop (540 psig) was checked, temperature was 68°F / °C.
  • Thus, (80°F / °C – 68°F / °C) x 0.79 = 9.5 psig.

(B) Triple Evacuation (Vacuum)

  •  Why is a triple evacuation so important instead of a deep vacuum? Because the relationship between pressure and temperature with water.
  • When the first vacuum is pulled, some of the moisture in the lines boils and evaporates.
  • However, once it reaches a certain pressure the water will actually freeze and leave small ice crystals in the system. This is why a single deep vacuum is insufficient.
  • A triple evacuation of all piping should be performed to eliminate moisture in the system:
  • Do NOT open service valves until the deep vacuum of 500 microns or below has been achieved and the additional charge has been added
  • If Heat Recovery System connect to all three main refrigeration stop valves at outdoor unit.
  • Verify that the micron gauge is connected at a point where it can read the system’s pressure at all times during this process, even when the vacuum pump is not running during the hold test.
  • Evacuation procedures: Evacuation procedures shall be performed as follows:
  • Step 1- Operate the vacuum pump and evacuate the system to the 2,000 micron level.
  • Isolate the pump by closing the manifold gauges and the vacuum pump valve, and then watch the micron level. Micron level may rise a bit, but MUST eventually stop rising for fifteen (15) minutes.
  • If the micron level DOES NOT stop rising, there is a leak, and the leak test must be performed again. If the micron level DOES rise above 2,000 micron, re-open the manifold gauges and the vacuum pump valve and continue evacuation back down to 2,000 micron level.
  • If the micron level holds at 2,000 micron, Break the vacuum with dry nitrogen to a pressure of 2-3 PSI and hold for 15 minutes (this is to “sweep” moisture from piping).
  • Step 2- Evacuate to 1,000 micron level.
  • Isolate the pump by closing the manifold gauges and the vacuum pump valve, and then watch the micron level. Micron level may rise a bit, but MUST eventually stop rising for fifteen (15) minutes.
  • If the micron level DOES NOT stop rising, there is a leak, and the leak test must be performed again.
  • If the micron level DOES rise above 1,000 micron, re-open the manifold gauges and the vacuum pump valve, and continue evacuation back down to 1,000 micron level. If the micron level holds at 1,000 micron, Break the vacuum with dry nitrogen to a pressure of 2-3 PSI and hold for 15 minutes (this is to “sweep” moisture from piping).
  • Step3- Evacuate to static micron level ≤500.
  • Micron level must remain ≤500 for 24 hours. If the vacuum gauge rises and stops, the system may contain moisture, therefore, it will be necessary to repeat the steps of vacuum break and drying.
  • After maintaining the system in vacuum for 24 hours, check if the vacuum gauge rises or not. If it doesn’t rise, then the system is properly evacuated.
  • Close manifold gauges.
  • Shut the valve before turning off the vacuum pump.

Refrigerant Charging:

  • Weigh in additional refrigerant with digital scales. Calculate charge based on total line length plus lb/ft of diameter. Check with each unit model for correct multiplier.
  • After the amount of refrigerant to be added is determined write it down on the label on the back side of the front cover. After the vacuum/drying is complete, charge the additional refrigerant in its liquid state through the liquid stop valve service port.
  • Make sure to use installation tools you exclusively use on R410A installations to withstand the pressure and to prevent foreign material from mixing into the system.

Gas Pressure For any Ton Capacity

Refrigerant Suction Pressure (PSI) Discharge Pressure (PSI) Standing Pressure (PSI)
M/C ON M/C ON M/C OFF
R 22 60 To 70 250To 300 156
R 32 120 490 260
R 134A 35 158 To 199 95
R 290 65 275 To 300 125
R 404A 87 270 To 356 190
R 407C 63 247 To 307 153
R 410A 110 To 120 400 To 500 250
R 417A 65 261 140

Refrigerant Piping –Additional Refrigerant Charge:

  • Do NOT open unit service valves until additional refrigerant charge has been calculated, added and recorded.
  • Calculates the additional refrigerant charge based on the refrigerant piping layout. If at any time there is a change in the actual piping installation from the design layout, it must be reported back to the designer for verification.
  • Enter additional refrigerant charge amount -R410A.Lbs.
  • Record additional charge amount inside the outdoor unit using a permanent marker.

Additional Refrigerant Charged Volume

Liquid pipe Size R410A (kg/m)
6.4 mm 0.022
9.5 mm 0.057
12.7 mm 0.11
15.9 mm 0.18
19.1 mm 0.26
22.2 mm 0.37
25.4 mm 0.45

Split AC Copper Pipe Additional Refrigerant Charge

Total Pipe Length 50 Meter 60 Meter 70 Meter
Additional Refrigerant None 250 gm (25gm/Meter) 500 gm (25gm/Meter)

Electrical Connections:

  • Make all electrical connections in accordance with electrical codes and ordinances.
  • Multi-pole circuit breaker or disconnect is required to fully isolate the unit from all power.
  • Install circuit breakers/disconnects in accordance with local and national codes.
  • Select the power cable in accordance with relevant local and national regulations.
  • Unbalanced power must be maintained within 10% of supply rating among all indoor units or the unit will stop and an error code will be generated. (Significantly unbalanced power may shorten the life of the system.)
  • Ground the unit at an exclusive grounding terminal, at the electrical panel
  • The communication cable between single-phase outdoor units and between indoor and outdoor units has no polarity.

Testing of the System:

(A) Indoor Unit Cooling Measurement:

  • Measure Indoor unit Return Air Temperature or Room Temperature.
  • Measure Indoor Unit Grill Temperature.
  • Grill Temperature should be 10⁰C to 13⁰C less than Room Temperature in 10 to 15 min.

(B) Outdoor Unit Hot Air Measurement:

  • Measure Outdoor Atmosphere Air Temperature near Out Door Unit (Fan inlet Temperature).
  • Measure Outdoor Unit Fan Discharge Temperature.
  • Outdoor Unit Fan Discharge Temperature should be 11⁰C to 14⁰C higher Out Door Unit Fan inlet Temperature.

(C) Measure Suction Pressure and Discharge Press of System

  • Suction and Discharge Pressure should be according to Refrigerant Type.

(D)Measure Cuurent drawn by Compressor.

  • Ampere drawn by should be as per Manufacture recommended Current Rating.

(E) Fell Cooling of Discharge Line (Liquid Line)

  • Discharge line should be cool enough after starting of Compressor.

(F) System Cooling Problems

  1. Less or No cooling even though No Leakage in Refrigerant Pipe & Suction Pressure is OK.
  • Low Discharge Pressure
  • Weak Compressor.
  1. Ice accumulation on Discharge Line (Liquid Line / Small Line)
  • Less Gas Pressure
  • Capillary Problem.
  1. Ice accumulation on Suction Line (Gas Line / Big Line)
  • Less Gas Pressure
  • Indoor Air Filter chock up, Blower Not running, indoor unit cooling coil problem.
  • Outdoor unit Fan speed is too low, Capacitor Discharge, Refrigerant Pipe Bend or punch
  1. Ice accumulation on both Suction & Discharge Line
  • Not Cut Off Compressor,
  • Electrical Contactor stuck , Electrical Contactor coil not working
  • Problem in Sensor, Thermostats.
  • Machine is continuous working 

System Problems

System Problem Discharge Line Pressure Suction Line Pressure Suction Line Temperature Compressor Amp
Over Gas Charge High High Low (Ice on Suction Pipe) High
Under Gas Charge Low Low High Low
Capillary Block Low Low High Low
Less Air Flow on Evaporator (Indoor Unit) Low Low Low Low
Less Air Flow on Condenser (Outdoor Unit) High High High High
Dirty Condenser (Outdoor Unit) High High High High
Low Ambient Temperature Low Low Low Low
High Ambient Temperature High High High High
In sufficient Compressor Low High High Low

HVAC System installation & Testing Flow Chart

Method for Installation of HVAC System (Part-3)


(C) Y Joints

  • Confirm the Y branching piping matches allowable designs from the Installation Manual

  •  Installed with single end of Y Joints always towards outdoor unit.
  • The branch joint of outdoor side must be installed horizontally.
  • The branch joint of indoor side can be installed horizontally or vertically.
  • Y Joints are supported before and after.
  • “Y” joints are the correct size and match the locations as shown on the Selection Report.
  • Maintain a minimum distance of 20″ between branching joints, headers, elbows and equipment.
  • Recommend horizontal runs to be 3 times that of the vertical when traps cannot be avoided

  • Between two branch joints ≥1m
  • Between branch joints and indoor unit ≥0.5m
  • From the inlet or outlet of branch joint, there should be straight pipe with length at least 0.5m

(D) Copper Pipe Length:

The permitted length and drop difference

Pipe length Max. pipe length <= 240 Meter
Equivalent length from the first branch to the farthest indoor unit <= 40 Meter
Drop height Drop height between indoor unit and outdoor unit <= 110 Meter
Drop height between indoor units <= 30 Meter

  • Record the actual liquid pipe length for future reference when charging additional refrigerant.

Split AC Copper Pipe Length

A.C Capacity Maximum Pipe Length Maximum Indoor & Outdoor Height Difference
0.5 Ton 15 Meter 5 Meter
0.6 Ton 15 Meter 5 Meter
0.75 Ton 15 Meter 5 Meter
1 Ton 20 Meter 10 Meter
1.5 Ton 25 Meter 10 Meter
2 Ton 25 Meter 10 Meter
2.5 Ton 30 Meter 10 Meter
3 Ton 30 Meter 20 Meter
3.5 Ton 30 Meter 20 Meter
4 Ton 30 Meter 20 Meter

(E) Drain Pipe

  • Water leakage test
  • Check leakage of water pipe After finished installation of drainage pipe, filled the pipe with water,
  • Waiting for 24 hours to check whether there’s any leakage.
  • Check leakage from the indoor unit
  • Charge water from the check hole of indoor unit to check whether the water can be exhausted smoothly or not

Size of Drain Pipe

Condensate water volume : V (L/h)=Indoor Unit (HP)x2  I.D (mm)  Thickness (mm)
V ≤ 14 Φ 25 3
14 V ≤ 88 Φ 30 3.5
88 V ≤ 175 Φ 40 4
175 V ≤ 334 Φ 50 4.5
334 V Φ 80 6
*If Slop is <1% than select next higher Size of Drain Pipe

(F) Insulation of Refrigerant Pipe & Drain Pipe

  • The slip-on method of installation is used for insulation on new refrigeration piping
  • The inside of the insulation is coated with a powdered lubricant, making it easy to slip the insulation over the pipe.
  • Small amounts of powdered lubricant may enter the open ends of pipe or tubing. This dust must be kept out of refrigeration systems. Plug the open ends of pipe before slipping on the insulation.
  • Apply insulation only when the pipes are clean, dry, and unheated or uncooled. The surface to be insulated must be free of rust.
  • Never stretch insulation when sealing the joints. It is better to compress it slightly. Use pieces of insulation that are at least as long as the section of pipe to be insulated.
  • Always use the insulation that is properly sized for the pipe it is to cover. Do not stretch it over the pipe.
  • Do not crowd insulation-covered pipes. Space pipes far enough apart to allow for the free circulation of air. Air movement is an extra safeguard against surface condensation of cold pipes, especially under hot, humid conditions.

  • All piping insulation must be properly sealed to minimize heat loss and control condensation. On cold lines, open pipe insulation joints may allow the formation of condensation, increasing the potential for or contributing to possible pipe or tubing corrosion. Seal insulation joints
  • Do not compress piping insulation at joists, studs, columns, ducts, hangers, etc. This is important because the insulation will lose thermal efficiency where it is compressed. On cold systems, surface condensation may occur where insulation is compressed
  • Apply a coating of an approved contact-type adhesive to both butt ends to be joined.

  • Before butting the ends together, allow the adhesive to set until it is dry to the touch but still tacky under slight pressure. Join the surfaces.
  • Cut open the inside wall of the elbow, taking care not to damage the opposite wall. The slit-open elbow should slip over the fitting. Apply adhesive to the seam (not to the butt ends), allow to tack dry, and fit over the fitting. Press the seams together working from the ends toward the center of the elbow.

  • Finally, wet seal the butt ends to the incoming lengths of insulation. Cut the incoming lengths so that the butt joints are in slight compression.

  • Do not wrap the gas and liquid refrigerant pipes together.
  • Avoid compressing the insulation as much as possible
  • Be sure there are no cracks or deformities in the insulation at bends in pipes.
  • If necessary double the insulation to prevent condensation from forming in warm or humid areas.
  • Cut off excess insulation.

 Referent Pipe Insulation

Pipe Pipe size Insulation Type (EPDM or NBR)

 

Standard conditions 86°F (30°C), < 85% High humidity conditions(a)
86°F (30°C), >85%
Liquid Pipe 1/4″ (6.35 mm)  To 3/8″ (9.52 mm) 3/8″ (9 mm) 3/8″ (9 mm)
1/2″ (12.70 mm)  To  2″ (50.80 mm) 1/2″ (13 mm) 1/2″ (13 mm)
Vapor Pipe 1/4″ (6.35 mm) To 7/8″ (22.23)  1/2″ (13 mm) 3/4″ (19 mm)
  • Wrap insulation around the entire surface of each pipe, including the refrigerant pipes from the indoor unit to the service valves inside the outdoor unit, the branch joints, distribution header, and connection points on each pipe.

  • Do not wrap the vapor and liquid refrigerant pipes together.
  • If vapor and liquid pipes are in contact with one another, use thicker insulation and make sure the pipes are not pressing tightly against one another.
  • Pipe connections between the indoor unit and EEV kit: Leave 3/8 in. (10 mm) of space between vapor and liquid pipes.
  • Be sure there are no cracks or deformities in the insulation at bends in pipes or where hangers are attached to pipes.
  • If necessary, double the insulation to prevent condensation from forming in warm or humid areas.

Insulation Thickness

Refrigerant Pipe Insulation Drain Pipe Insulation
22.22mm To 28.58mm 19mm 25mm / 32mm /40mm 6mm
12.7mm To 19.05mm 13mm / 19mm
6.35mm To 9.2mm 9mm / 13mm

Method for Installation of HVAC System (Part-2)


Indoor Unit Installation:

(a) High Wall Unit:

  • The installation of the split air conditioners is a crucial job. If the installation is done accurately  air conditioner will give optimum cooling, but if it is not done properly we won’t get the desired cooling effect. A poor installations also leads to frequent maintenance problems.
  • Several factors have to consider during the installation of split air conditioner.
  • Strength of wall to hold the AC
  • The indoor unit of split AC must be installed on a wall strong enough to hold the unit’s weight.
  • Proper spacing between wall and AC unit
  • The indoor unit of split AC requires at least 15 cm of open space surrounding its top and sides for proper air flow.
  • Appropriate installation height from ground
  • Mount the indoor unit of split AC at a height of 7 to 8 feet above the ground for adequate cooling inside the room
  • Correct tilt angle of indoor unit
  • While fixing the aluminum bracket on wall make sure that the bracket is given a slight tilt angle, so that the indoor unit of split AC, when fitted is also at a slight angle to enable unrestricted flow of the condensed water from the drain pipe.

(b) Cassate Type:

  • Air inlet and outlet should be clear of obstructions, ensuring proper airflow throughout the room.
  • Condensate can be easily and safely drained.
  • A structure strong enough to withstand four 4 times the full weight and vibration of the unit.
  • Filter can be easily accessed for cleaning.
  • Leave enough free space to allow access for routine maintenance.
  • Do not install in a laundry room or by a swimming pool due to chemical sorrowing cassette coil.

  • Indoor Unit Hanger Mounting Depending on the type of ceiling, attach the threaded hanger bolts securely to the support stud. Before lifting the indoor unit to the installation location, insert the upper nuts, flat washers (with insulation), flat washers (without insulation), lower nuts and double locking nuts on the threaded hanger bolts.
  • Lift the Ceiling Cassette main body to the threaded hanger bolts. Insert the unit mounting brackets between washers and then fasten it securely.
  • Pack the indoor unit with plastic bag after hoisting to protect them from dust entering.

Louvers:.

  • Allow for ventilation intake and exhaust air based on maximum outdoor unit fan capacity.
  • Select the size, type and orientation of architectural louvers with adequate “net free area” face velocity to ensure the total external static pressure from the outdoor unit fan does not exceed design limitations.
  • No obstructions must be placed in front of the louver that could hamper the free flow (throw) of air.
  • Roof top openings and / or discharge and supply louvers must be equipped with screens to prevent bird and insect infiltration.
  • Louver Angle is not more than 15 Deg Horizontally
  • Space between Louvers is not more than 4 inch
  • If louver open rate is too small it will create noise from louver blade vibrations. Insufficient air flow exchange creates drop in outdoor unit performance and may create air conditioner stop operating.

Refrigerant & Drain Pipe Installation Work:

(a) Pipe Support:

  • A properly installed pipe system will have sufficient supports to avoid pipes from sagging during the life of the system.
  • Sag­ging pipes become oil traps that lead to equipment malfunction.
  • Pipe supports must never touch the pipe wall; supports shall be installed outside (around) the primary pipe insulation jacket. Insulate the pipe first because pipe supports shall be in­stalled outside (around) the primary pipe insulation jacket.
  • Field provided pipe supports must be designed to meet local codes. If allowed by code, use fiber straps or split-ring hangers suspended from the ceiling on all-thread rods (fiber straps or split ring hangers can be used as long as they do not compress the pipe insulation). Place a second layer of insulation over the pipe insulation jacket to prevent chafing and compression of the primary insulation in the confines of the support clamp.
  • As necessary, place supports closer for segments where potential sagging could occur. Maximum spacing of pipe supports shall meet local codes. If local codes do not specify pipe support spacing, pipe shall be supported:
  • Wherever the pipe changes direction, place a hanger within twelve 12 inches on one side and within twelve 12 to 19 inches of the bend on the other side. Support piping at indoor units, Y-branch, and Header fittings
  • Supports must be strong enough. The supports should be full thread booms, and their diameters should be ≥ 10mm.
  • Dual nuts should be adopted to fix the indoor unit under the ceiling.
The distance between the supports of the copper pipes.
Diameter Distance (m)
 ≤ 20 mm 1 Meter
20 To 40 mm 1.5 Meter
 ≥ 40 mm 2 Meter

(b) Cutting & Welding of Refrigerant Pipe:

  • Install piping to be as short and direct as possible, with a minimum number of joints, elbows and fittings. Piping must be installed parallel to the building lines..
  • Pipes must be cut accurately to measurements established on site and must be worked into place without springing or forcing.
  • Pipes must be installed as permit free expansion and contraction without damage to joins or hangers.
  • All piping shall be installed in accordance with the mechanical design. Any deviation shall be submitted for prior approval to the mechanical engineer prior to installation.
  • Refrigerant piping diameter, thickness, and temper is selected according to length, as specified in this section.
  • Cut or extend field-supplied piping as needed. To extend pipes, braze or using flared pipe connections Refer to “Pipe Cutting,” “Nitrogen Flushing While Brazing,” and “Flared Pipe Connections,”
  • Make sure that pipes are free of dirt, debris, and moisture, and do not leak.
  • Braze or use flared pipe connections to install piping. Refer to “Connecting Piping to the Single- Phase Outdoor Unit,”
  • Pipe Cutting
  • Using a pipe cutter, cut the pipe so that the cut edge is at 90° to the side of the pipe.
  • Use a reamer to remove all burrs at the cut edge. Examples of correctly and incorrectly cut pipes.

  • Selected copper tube must be of suitable wall thickness for higher operation pressures.
  • Use a tubing cutter, do not use a saw to cut pipe. De-bur and clean all cuts before assembly
  • Brazing:
  • While brazing refrigerant pipes, flush them with nitrogen gas. Use a pressure regulator to maintain a flow rate of 1.76 ft3/h (0.05 m3/h) or more.
  • Dry Nitrogen: Dry nitrogen must be used during all brazing (pressure regulated to 3 PSI) to prevent copper plate or oxidation formation.
  • Always use a non-oxidizing material for brazing. Do not use flux, soft solder, or anti-oxidant agents. If the proper material is not used, oxidized film may accumulate and clog or damage the compressors. Flux can harm the copper piping or refrigerant oil.
  • Requirement of welding:
  • When welding the copper pipe, nitrogen is necessary to protect the copper pipe.The pressure of the nitrogen is 0.02 MPa
  • Charge the nitrogen to the copper pipe at the beginning of welding and only.when the copper is fully cooled down, the nitrogen can be removed
  • If Nitrogen is not used, Welding will create Oxide on copper pipe inside and outside, which cannot be removed and it jams the refrigerant flow and damage the Compressor.

  • Warning:
  • Do not braze in an enclosed location. Do not allow the refrigerant to leak during brazing. Always test for gas leaks before and after brazing.
  • Do not allow the refrigerant to leak during brazing; if the refrigerant combusts, it generates a toxic gas. There is risk of fire, explosion, and physical injury or death.
  • Flaring: Flared tube ends should have a smooth, even round flare of sufficient length to fully engage the mating surface of the flare nut, without protruding into the threads.
  • Use a flaring tool specifically designed for flare joints in R-410A systems, which creates deeper flares than those by made by traditional flaring tools. This flaring tool has an eccentric mandrel and clutch type handle. Follow the flare tool manufacturer’s directions for using the tool.
  • Slide the flare nut over the pipe to be flared. Slide the end of the pipe into the hole on the flaring bar that fits the pipe, leaving a length of pipe, determined by tool type (see table), extending above the flaring bar. Clamp it down.
  • Remove the pipe. The end of the pipe that you flared should look like the end of a trumpet. See examples of correctly and incorrectly flared pipes.

Method for Installation of HVAC System (Part-1)


Purpose:

  • This method explains the Procedures or sequence of activity for safely and efficiently installation and Testing of Refrigerant Pipes , Drain Pipes ,Indoor and Out Door Unit of HVAC System as per standard Practice and Code.

General Equipment & Tools:

  • The equipment that will be engaged for Installation of Cable works will be
  • Lifting crane , Transportation vehicle, Fork Lift
  • Winches, Pulling Rope , Welding machine
  • Lubricant (Soap based, wax based), Cleaning agent (CRP)
  • Copper pipe Flaring tools
  • Vacuum Pump,
  • Brazing Torch , Brazing Rod , Oxy-Acetylene Brazing Kit ,Wire Brush
  • Nitrogen Cylinders , Soldering Tools
  • Crimping tool, Drilling Machine with various Bits , Grinding Machine , Cutting Machine
  • Electrical Tool Box, Cable Cutter, Screwdriver, Pliers, Spanner.
  • Ladder , Scaffolding / Mobile scaffold
  • Nylon rope, Marker , Leveling device , Tape measure
  • Removable Barricades , Portable Lights
  • Testing Equipment for System
  • Multi meter ,Clamp Meter
  • Refrigerant / Nitrogen cylinder,
  • Vacuum Gauge

Storage & Material Handling:

  • The storage area must be free from dust and Water leakages / seepages.
  • Manufacturer recommendation shall always be followed in loading/unloading and storing of Material.
  • Material and its accessories shall be unloaded handle with care in designated area of the Store (Do not directly drop to Ground) to avoid any damages.
  • Materials shall be stored in a dry place which is free from water or from weather effects and protection should be given to the material by means of covering the material with Tarpaulin sheet.
  • The Material will be stacked / unload in the site store on a proper stand on wooden loft on a flat surface at a sufficient height from Ground.
  • The A/C Units should be kept on the wooden platform and covering with polythene to protected from any dust or mechanical damages
  • For storing the copper pipes:
  • If pipes will be used soon, nozzle should be sealed by plastic bag or tape.
  • If pipes will be stored for a long time, the pipes should be charged into 0.2 to 0.5MPa Nitrogen and the nozzle should be sealed by welding.

Inspection of Materials:

  • Check The Material according to its Type, Size, Make
  • Physical Damages Inspection:
  • Damage on Pipes and Units.
  • Damage on insulation of Cable
  • In case of any damages observed during inspection, the Material shall be returned to the supplier for replacement.

 Installation of Outdoor Units :

 (a) Transporting / Lifting the Outdoor Unit

  • Use appropriate moving equipment to transport outdoor Unit, ensure the equipment is capable of supporting the weights. When lifting the unit, use lifting straps and place around the unit.
  • Always lift the unit using appropriate size of lifting straps rated to carry the unit weight and long enough to maintain a maximum of a 40° angle as shown.
  • When moving / adjusting the placement of the outdoor unit, always hold the unit by the corners. Moving the outdoor unit using the side intake holes on the frame may damage the frame.
  • Consider the unit’s center of gravity before lifting. Hoist the unit with the center of gravity centered among the lifting straps. There is a risk of the product falling and causing physical injury.
  • Lift the outdoor unit from the base at specified locations. Support the outdoor unit at a minimum of six points to avoid slippage from the rigging apparatus.
  • Do not lay the unit on its side and do not slant the unit more than 30 degrees.

  • On a supporting structure that can bear the weight of the outdoor unit. The supporting structure can be a base on the ground, on a waterproof roof, or in a pit. With sufficient clearances around the unit for service and repairs. In a well-ventilated location. Away from strong wind.
  • Away from direct exposure to rain or snow. Where there is no risk of flammable vapor leakage. Where there is no exposure to salt, machine oil, sulfide gas, or corrosive environmental conditions.

(b) Selecting the Best Location for the Outdoor Unit(s)

  • Don’ts:
  • Do not install the unit in an area where combustible gas may generate, flow, stagnate, or leak. These conditions can cause a fire.
  • Do not install the unit in a location where acidic solution and spray (sulfur) are often used or in environments where oil, steam, or sulfuric gas are present.
  • A location that allows for optimum air flow and is easily accessible for inspection, maintenance, and Where piping between the outdoor unit and indoor unit(s) / heat recovery units are within allowable Limits.
  • Avoid placing the outdoor unit in a low-lying area where water could accumulate.
  • If the outdoor unit is installed in a highly humid environment (near an ocean, lake, etc.), ensure that the site is well-ventilated and has a lot of natural light (Example: Install on a rooftop).
  • Where operating sound from the unit will disturb inhabitants of surrounding buildings.
  • Where the unit will be exposed to direct, strong winds.
  • Where the discharge of one outdoor unit will blow into the inlet side of an adjacent unit (when installing multiple outdoor units).

  • If the outdoor unit is not placed on a roof, place it on the leeward side of the building or in a location where the unit will not be ex­posed to constant wind.
  • If placement exposes the unit to constant wind activity, construct a wind break in front of the unit. Follow the placement guidelines set

  • Avoid installing the outdoor unit where it would be directly exposed to ocean winds.
  • Install the outdoor unit on the side of the building opposite from direct ocean winds.
  • Select a location with good drainage and periodically clean dust or salt particles off of the heat exchanger with water.
  • Ocean winds may cause corrosion, particularly on the condenser and evaporator fins, which, in turn could cause product malfunction or inefficient performance.
  • If the outdoor unit must be placed in a location where it would be subjected to direct ocean winds, install a concrete windbreaker strong enough to block any winds. Windbreaker height and width must be more than 150% of the outdoor unit, and be installed at least 27.5 inches away from the outdoor unit to allow for airflow.

  • Rubber anti-vibration pads are necessary to avoid vibration.

  • Foundation can be made of channel steel or concrete.

  • Reserve the space for discharging condensate water from outdoor units.
  • The outdoor unit should be placed neatly, and reserve enough space for maintenance.
  • The outdoor unit should be installed in the place that is dry, well-ventilation and close to the indoor units.

Method for Installation of Cable & Wire (Part-2)


(A) Cable Laying in Excavated Ground:

(a) Formation of Cable Trench.

  • Check the area of excavation by referring As Built drawing to find out crossing of any underground Services i.e. Gas Line, Water Line or other Cable. Check the indication marks, signs, manholes nearby area and find out the path of old services.
  • If there are structures adjacent to the work area, proper temporary supports shall be provided to the adjacent structure prior to start excavation.
  • Excavation near the existing electrical cables, instrumentation and control cables, sewer line, gas lines and any other service line shall take all necessary precautions to protect the services with proper supports & covers.
  • Ensure the working area at any confined space is free from any Hazardous Gas by proper Gas testing using the Gas testing instrument.
  • Required sign boards such as “DEEP EXCAVATION” “MEN WORKING”, “DANGER” and warning boards will be placed to indicate the excavation work. The area of excavation will be cordoned by using safety barricading to stop trespassers.
  • In open areas the excavation shall be carried out by using the machineries.
  • If the excavation level is below the local water table level suitable dewatering system shall be designed and installed in such a way that alterations and extensions to the system during operations are possible.
  • The width of the excavated Cable trench shall be as per specification or as per approved Drawings.
  • The trench shall be excavated up to the required depth of 0.76 Meter from the existing ground level or as per Specification or as per approved Drawing.
  • The Cable trench shall be kept dry during cable installation operation. The contractor shall deal with the dispose of water so as to prevent any risk to the cables and other materials.
  • Debris, rocks and unusable materials shall be removed from Excavated Trench on daily basis and it will dump at the approved dumping Location of from the site.

(b) First Layer of Sand:

  • The bottom of the trench shall be backfilled with a layer of clean and fine sand bedding of 100mm thickness or as per the approved Drawing.
  • The fill material shall be tamped. Any hard material which could damage the cable will be removed
  • Inspection of sand bed will be carried out prior to commencement of cable pulling.

(c) Cable Laying:

  • Cables are laid over the clean and fine First Layer of sand bedding.
  • Rollers must be used where cables are installed in an open trench using a pulling rope and eye; cable rollers are to be used at frequent intervals to support the cables and must never be more than 3 meters apart.
  • Care must be taken to ensure that the cable does not enter or leave the rollers at an angle that exceeds the bending radius of the cable.
  • The Pulling rope must be attached to the cable by a stocking grip with pulling eye.
  • The cable shall be drawn into the trench manually, before the pull commences, to prevent the winch to move along with the cable.
  • The cable shall be drawn into the trench smoothly with a minimum of stops and at an average speed of between 9 to 12 meters per minute, to avoid irregular movement.
  • Cables shall be arranged properly to minimize crossovers, twists.
  • All Cable shall be laying parallel to each other and cable dressing should be done properly
  • Cable identification tags shall be installed on both end of cable after the cable pulling.

(d) Second Layer of Sand:

  • The cables shall be backfilled with approved clean and fine Sand / backfill Material of 100mm thickness or as per the approved Drawing.
  • The fill material shall be tamped. Any hard material which could damage the cable will be removed
  • Inspection of sand bed will be carried out prior to commencement of Cable Protection layer.

(e) Cable Protection:

  • Cable protection tiles / Bricks / Warning Taps are laid above the second layer of dune sand filling.

(f) Back Filling:

  • Backfilling materials shall be free from stones or rocks (larger than 50 mm), fossil content, vegetation and its roots, waste materials, Material containing gypsum or other soluble salts greater than the allowable limits which might prevent proper compaction or cause to inadequately of performance.
  • Backfilling area shall be backfilled with approved material compacted in layers by suitable equipment like plate compactors, vibratory roller compactors, etc., until the specified density has been obtained.
  • Sufficient Water is poured to match the required Moisture content.
  • Intermediate cable markers to be firmly attached to the cables.
  • The thickness of fill material shall not exceed 150 mm where manual compaction methods are adopted.

(B) Cable Laying in Cable Tray / Trunking:

  • Before laying of Cable , Cable Tray work should be completed form the one end to other end of the Cable route
  • The cable tray must be cleaned and free from any dust or water dampness, before pulling the cables.
  • Use cable rollers in cable trays to avoid damage on cables during the pulling process.
  • From cable reel to cable tray, the cable is fed from the top of the reel to maintain required curvature. Sheaves, or a shoe, may be used to guide the cable into the tray.

  • Cable rollers shall be placed at every 6-12 meters or less if required to avoid touching of the cable to tray.
  • Cable laying will generally start from one end of the route length from other suitable point if required.
  • The number and size of cables drawn in to a particular cable tray shall not be exceed that allowed in specifications.
  • At any time of Cable laying only one cable should be laid on cable tray, after laying first cable necessary dressing and cable tie should be fixed than after that second cable should be lay.
  • Cut the cables to required length at both ends, seal the ends with adhesive insulation tape roll and keep in the box or enclosures to ensure no damage can occur to cables.
  • Cables shall be arranged properly to minimize crossovers, twists
  • Control cables will be laid along the LV cables. HV cables to be laid in separate trays
  • All control cables will be installed at a minimum distance of 100mm from power cables unless otherwise agreed with consultant as per site conditions.
  • After completion of all cables in the same route the cables shall be dressed and clamped.
  • All cables in horizontal or vertical runs will be secured to the trays by nylon fasteners / ties.
  • Cable identification tags as per specifications shall be installed on both end (at sending and receiving ends) of cable after the cable pulling.

(C) Cable Laying in the Building

  •  In case of Cable lay inside the buildings, the drums will be placed outside the buildings and the cable pulled in the opposite direction. After reaching the other end the length of the cable required for reaching the location inside the building will be measured and then cut the cable.
  • The cable is fed from the cable reel directly into the conduit at floor level.
  • The cable is fed from the bottom of the reel so that its curvature is continuous with no reversed bends.

  • Do not pull cable directly across short, sharp angles. After pulling completely out of one side of the enclosure, feed cable into the other side of the enclosure and pull that segment
  • Unloading equipment should not come in contact with the cable or its protective covering.

(7) Wires Pulling in Conduit:

  • Proper marking / selection of location on site to be done prior to commencement of installation works.
  • Complete a mockup installation before main works and get its approval.
  • Make sure that all conduits and boxes in both ends are free from damages and blockages etc and installation is approved.
  • Blockage shall be checked by inserting the draw wire and checking that it reaches to the other end without any disturbance.
  • Use of Steel fish wire shall be made for drawing of wires. Wires shall be drawn with adequate care.
  • Once the conduit is not blocked the wires shall be pulled using the draw wires while ensuring no damage occurs while pulling.
  • Pulling compound or lubricant shall be used for pulling the wires where required.
  • Use soap based pulling compound for short runs i.e. less than 20 meters for semi conductive insulated wires.
  • Use wax based pulling compound for the runs greater than 20 meters for semi conductive insulated wires.
  • While pulling the wires care should be taken to not insert the pull tension greater than the manufacturer allowed limits.
  • Separate conduits shall be run for lighting and power circuits and also for telephone cables. To avoid any cross talk and extraneous interference in the telephone circuits, all telephone wiring conduits shall be run with a sufficient clearance from the power and lighting conduits.
  • All separate circuits from DB’s shall have separate neutral to the points. Common neutral between separate circuits are not permissible.
  • As far as possible wiring shall be run in conduits. All conduit wiring shall be complete with continuous earth as per I.E.R.
  • The wiring shall be carried out as specified.  ‘Power’ and ‘heating’ wiring shall be kept separate and distinct from ‘Lighting’ wiring. The wiring shall be done on the distribution system with main and branch distribution boards at convenient physical and electrical centers and consideration shall be given for neatness and good appearance.
  • The wiring shall be done in the ‘Looping System. ‘Phase’ or ‘live’ conductors shall be looped at the switch box and neutral conductor can be looped from the light fan or socket outlets.
  • 5 sq. mm PVC wires in green color are to be run continuously in conduits for continuous earthing. The earth wire should be connected to GI Switch boxes and DB boxes by tapped screws.
  • No bare or twist joints shall be made at intermediate points in the through run of cables.
  • Bare or twist joints shall be carried out with due care and preferably through proper junction boxes.
  • If any joint becomes unavoidable such joints shall be made through proper cutouts or through proper junction boxes open to easy inspections.
  • Electrical Load should be balance on all the three phases for an even distribution. Before commencement of work, the contractor shall seek the approval of the Consultants / Site Engineer on the distribution of balancing of loads and circuits. The wiring shall be done by the process of looping the live conductors and the neutral wires. 
  • Color coding of wires
  • Phase : Red, Blue, Yellow,
  • Neutral: Black,
  • Earth: Green.
  • Adequate extra length shall be left at termination points. 

(8) Excess or Spare Cable Storage:

  • Store Cable reels on hard surface so that the flanges will not sink and allow reel weight to rest on cable.

(9) Cables Identification / Marking of Cables:

  • Install the tags / labels as per project specifications and as per approved material submittals.
  • Cable marking shall be positioned properly to read and identify
  • For Buried / Surface mounted cables tagging / Labeling will be corrosion resistant tags (with engraved or stamped for the identification number of the cable, voltage Rating, conductor size and make) or as per project specifications and as per approved material submittals.
  • Cables shall be identified at feeders i.e. the sending and receiving ends (outgoing cables in SMDB’s and final DB’s) about 50mm below the gland.
  • All termination shall be provided with tight fitting covering sleeves.

(10) Duct Seals:

  • After installation of all Cables, all cable ducts / Hume Pipes / Sleeves entering substations and buildings to be duct sealedto prevent the ingress of water and gas.

(11) REFERENCES

  • IEC 60228, BS 6360.
  • BS 5467.

(12) Flow Chart:

  

Method for Installation of Cable & Wire (Part-1)


Purpose:

  • The method explains the Procedures or activity for safely installation and Testing of MV cable in directly buries in ground, in trenches, in to cable trays or in underground ducts as per the standard Practice and Code.

General Equipment & Tools:

  • Testing Equipment for Cable
  • LV / HV Insulation Resistance tester (250V to 5KV)
  • Multi-meter
  • Continuity Tester
  • AC High Voltage Test Kit

Storage & Material Handling:

  • The storage area must be free from dust and Water leakages / seepages.
  • Manufacturer recommendation shall always be followed in loading/unloading and storing of Material.
  • Material and its accessories shall be unloaded handle with care in designated area of the Store (Do not directly drop to Ground) to avoid any damages.
  • Materials shall be stored in a dry place which is free from water or from weather effects and protection should be given to the material by means of covering the material with Tarpaulin sheet.
  • The Material will be stacked / unload in the site store on a proper stand on wooden loft on a flat surface at a sufficient height from Ground.
  • If Material are dispatch in packs or pallets, each pack or pallet shall be lifted individually with suitable lifting equipment.
  • The material shall be transported / Shifted in their original packing to Site location.
  • The cable drums shall be off-loaded at the site locations.

  • The cable drum should be visually inspected for damage, which may have occurred during transport.
  • During storage periodical rolling of drums once in 3 months done. Rolling shall be done in the direction of the arrow marked on the drum.
  • It should be ensured that both ends of the cable are properly sealed to prevent ingress/absorption of moisture by the insulation.
  • Protection from rain and sun shall be ensured. Sufficient ventilation between cable drums, should be ensured during storage.
  • The drums shall always be rested on the flanges and not on the flat sides. f. Damaged battens of drums etc. should be replaced, if necessary.
  • When cable drums have to be moved over short distances, they should be rolled in the direction of the arrow, marked on the drum
  • While transferring cable from one drum to another, the barrel of the new drum shall have a diameter not less than that of the original drum.
  • The manufacturer’s seal on the inner and outer cable ends should be examined and the condition of the sheath inspected for mechanical damage.
  • If the cable is found defective it shall not be installed and the cable shall be returned to the supplier for replacement.

Inspection of Materials:

  • Check The Material according to its Type, Size, Make
  • Inspection of Cable:
  • Type of Cable (HT /MV /LV)
  • Cable Operating Voltage
  • No of Cable Core (1 core,2core,3 core, 3.5 Core,4 core)
  • Type of Cable Core (Cu, Alu)
  • Type of Cable Material (PVC,XLPE)
  • Size of Cable
  • Length of Cable
  • Physical Damages Inspection:
  • Damage on Cable Drum
  • Damage on insulation of Cable
  • In case of any damages observed during inspection, the concern report will be issued and Material shall be returned to the supplier for replacement.

Testing and of Cable:

(1) Insulation resistance test:

  • Following Insulation resistance test will be carried out by approved calibrated equipment.
  • At the Time of Cable drum receiving at the Store
  • Before Installation of Cable on Site.
  • After Installation of Cable on Site.
  • The Insulation Resistance values will be noted for Core to Core and Armor by DC High Voltage Tester (Megger) before following activities.
                                    Voltage Class Test instrument Acceptance Value
L/V Cable 1000 VDC >20 Mega ohm
M/V Cable 5000 VDC >100 Mega ohm
Control, Instrumentation, Communication cable 250 VDC >1 Mega ohm
  • The cables and conductors must discharged after Insulation Resistnce test.

(2) The continuity test:

  • The continuity test would be carried out between
  • Phase to Phase,
  • Phase to Neutral,
  • Phase to earth and
  • Neutral to Earth.
  • The results would be recorded for records and future reference.
  • After the test, the end of the cable shall be sealed to prevent the ingress of moisture.

General Steps for Cabling Laying

  • Shifting of Cable Drum at Working Location:
  • If a crane is used to unload / Shift cable, a shaft through the arbor hole or a cradle supporting both reel flanges should be used.
  • Forklifts must lift the reel by contacting both flanges.
  • Check and ensure that approved drawings, the correct size and type of Cable & accessories are ready for installation.
  • Ensure that Cable and accessories received from site store for the installation are free of rusty parts and damages.
  • Installation of Cable Drum on Jacks:
  • Check and ensure that the Correct Size and Type of Cable Drum and accessories are transported at the Site locations.
  • Ensure that cable and its accessories received from site store for the installation are free from rust, corrosion and damages
  • Location of cable drum should be planned before transportation of cable drum. (Practically could differ at one or two places for easy installation of cable).
  • The cable drums shall be un-packed.
  • Depending on the weight and size of the drum, suitable size of the cable spindle shall be placed inside the central axis of the drum.
  • Suitable jacks shall be placed firmly on the ground and jacked-up the Drum to allow sufficient clearance from the ground. Ensure that the cable drum on a jack is free for rotation.
  • The cable drum will be correctly positioned and the direction of cable pulling as indicated by arrow on the drum shall be complied.
  • Drum control during pulling
  • Cable winch, if required, shall be positioned in proper place for cable pulling.
  • The cable shall be fixed to the winch, if used, by means of a cable sock or gripper. Required number of persons will be posted at winch and near the drum.
  • At all times during the pulling operation, at least one member of the team shall be stationed at the drum to control its rotation and check on the stability of the drum and jacks.
  • Cable Roller:
  • Cable rollers shall be placed as required on the cable route.
  • Cable rollers will be placed not more than more than 3 meters apart under the M.V cable during pulling over longer distances and standoff rollers for acute bends to ensure that the cable is pulled with minimum effort and the cable outer jacket is free of scouring lines.
  • Cable Pulling Speed:
  • The required cable pulling speed and tension requirement shall be maintained according to the manufacturer’s specification. If any problem arises during the pulling, the proceedings shall be stopped immediately and restarted only after the problem has been cleared.
  • The pulling speed shall be controlled during the cable pulling and it will be assured by observing the indication of the tension meter.
  • Cable pulling shall be done under strict supervision during the entire period of operation. Safety norms shall be observed and shall stick to the standard requirements
  • Identify Cable Laying Route:
  • Location of the panels / equipment shall be identified.
  • Cable laying will generally start from one end of the route length or at any suitable point if required.
  • In case of cable lengths which are more than one drum length, all cables which can be laid from original position will be completed. And then the cable pulling set-up will be re-positioned to the next location, from where the next length will be pulled.
  • Cables shall be cut from the drums as per the actual cable length in accordance to the drum schedule and drum allocation sheets
  • Before cutting the cable, both ends must be inspected to ensure sufficient length is for proper dressing and end termination.
  • The cable schedule and drum schedule will be updated with the information on cable pulling.
  • Cable rollers shall be positioned properly in to the cable trench. The intervals for the rollers are to be kept approximately 2 to 3 meters.
  • The rollers shall be maintaining its smooth rotation. If the cable will run through the curves and edges the, curve rollers should be used at the proper position in order to keeps a safe cable bending.
  • Precaution while laying of Cable:
  • Where bends are encountered in a run, cables shall be lubricated with a cable pulling lubricant (without Petroleum based) to facilitate easy movement.
  • Ensure excessive force and twisting of cables is avoided
  • Proper spacing will be maintained between the cables
  • Cables are protected from mechanical damage during pulling
  • Protection shall be provided to the cables at crossings with pipes, civil works to prevent mechanical damage.
  • PVC sleeves shall be installed for all cables passing through brick, block or concrete or similar structures in case there is need for future withdrawal.
  • After the Insulation Resistance Test, the open ends of the cable will be sealed till termination to prevent entry of Moisture and water.
  • After completion of all cables in the same route the cables shall be dressed and clamped.
  • Unless the lengths exceed the maximum drum lengths joints shall be avoided. Joint markers indicating joint positions shall be provided above ground and also shown on the drawings.
  • Empty cable drums will be transported back to stores.
  • Measure Insulation Resistance before Laying Cable
  • Insulation resistance of the cables shall be checked before laying cables.
  • Measure Insulation Resistance After Laying Cable
  • Soon after completion of every cable laying the cables will be tested for insulation resistance.
  • Cable Bending Radius:
  • During installation process cable can not be bent to a radius of less than 6D for unarmored cable and 8D for armored cable or bending radius of cables shall comply with cable manufacturer’s recommendation. These conditions shall be strictly follow to, particularly where cables turn into road crossings, conduit entry etc
  • Eliminate Sharp Edge:
  • While pulling, in order to eliminate sharp bend and crossovers, always have a person feed the cable(s) straight into the conduit by hand or, for larger cables, over a large diameter sheave.

  • Do not pull cable directly across short, sharp angles. After pulling completely out of one side of the enclosure, feed cable into the other side of the enclose and pull that segment.

  • Cable Laying Arrangements:

  • The configuration of three single-conductor cables in a conduit is determined by the ratio of the conduit inner diameter (D) to the outer diameter (d) of one of the single cables (D/d ratio).

  • A cradled configuration develops when three single-conductor cables are pulled into a conduit where the D/d ratio is 2.5 or greater.
  • A triangular configuration develops when three single conductor cables are pulled into a conduit where the D/d ratio is less than 2.5.
  • These cables may be pulled from individual reels, tandem reels, or a single reel with parallel wound cables.

Quick Reference -HVAC (Part-2)


A.C Capacity

Ton KW H.P
0.64 2.1 0.8
0.80 2.8 1
1.00 3.7 1.25
1.28 4.6 1.6
1.60 5.6 2
2.00 7.31 2.5
2.56 9.35 3.2
3.20 11.6 4
4.00 14.4 5
4.48 16.7 5.6
6.40 22.1 8
8.00 29.1 10
1TON= 1TON=3000 K.Cal/Hr
1TON=1200 BTU/Hr
1TON=3.516 KW
1TON=1.25 HP (VRV / VRF Only)
1TON=4.7 HP
1TON=12660 KJ/Hr

Split AC Copper Pipe Size (Blue Star)

A.C Capacity Suction Pipe Discharge Pipe (Liquid)
Up to 1 Ton 12.7mm (1/2″) 6.4mm (1/4″)
1 To 4 Ton 15.9mm (5/8″) 9.5mm (3/8″)
5 To 6 Ton 19.1mm (3/4″) 9.5mm (3/8″)
7 To 8 Ton 22.2mm (7/8″) 12.7mm (1/2″)
9 To 11 Ton 28.6mm (1 1/8″) 12.7mm (1/2″)
12 To 19 Ton 28.6mm (1 1/8″) 15.9mm (5/8″)
20 To 27Ton 34.9mm (1 3/8″) 19.1mm (3/4″)
28 To 42Ton 41.5mm (1 5/8″) 19.1mm (3/4″)
Normal Split A.C Copper Pipe Maximum Length = 15Meter
VRV System Copper Pipe Maximum Length = 150Meter

Split AC Copper Pipe Length

A.C Capacity Maximum Pipe Length Maximum Indoor & Outdoor Height Difference
0.5 Ton 15 Meter 5 Meter
0.6 Ton 15 Meter 5 Meter
0.75 Ton 15 Meter 5 Meter
1 Ton 20 Meter 10 Meter
1.5 Ton 25 Meter 10 Meter
2 Ton 25 Meter 10 Meter
2.5 Ton 30 Meter 10 Meter
3 Ton 30 Meter 20 Meter
3.5 Ton 30 Meter 20 Meter
4 Ton 30 Meter 20 Meter

Split AC Copper Pipe Additional Refrigerant Charge

Total Pipe Length 50 Meter 60 Meter 70 Meter
Additional Refrigerant None 250 gm (25gm/Meter) 500 gm (25gm/Meter)

Copper Pipe Thickness

Pipe Size Thickness Tube Gauge Type
6.4mm (1/4″) 0.8 mm 21 Soft
9.5mm (3/8″) 0.8 mm 21 Soft
12.7mm (1/2″) 0.8 mm 21 Soft
15.9mm (5/8″) 1 mm 19 Soft
19.1mm (3/4″) 1 mm 19 Soft
22.2mm (7/8″) 1 mm 19 Hard
28.6mm (1 1/8″) 1.2 mm 18 Hard
34.9mm (1 3/8″) 1.2 mm 18 Hard
41.5mm (1 5/8″) 1.3 mm 18 Hard
De-Oxidized Copper Tubes (DHP) , Copper 99.9%
Soft Copper as per ASTM B68
Hard Copper as per ASTM B75 / ASTM280 / BS 2871

Gas Pressure For any Ton Capacity

Refergerent Suction Pressure (PSI) Discharge Pressure (PSI) Standing Pressure (PSI)
M/C ON M/C ON M/C OFF
R 22 60 To 70 250To 300 156
R 32 120 490 260
R 134A 35 158 To 199 95
R 290 65 275 To 300 125
R 404A 87 270 To 356 190
R 407C 63 247 To 307 153
R 410A 110 To 120 400 To 500 250
R 417A 65 261 140
Nitrogen Pressure Test

Vacuum

3 Minutes 150 PSI <= 500 Micron for 24 Hours
5 Minutes 325 PSI
24 Hours 500 PSI
vacuum < 500 Micron

System Problems

System Problem Discharge Line Pressure Suction Line Pressure Suction Line Temperature Compressor Amp
Over Gas Charge High High Low (Ice on Suction Pipe) High
Under Gas Charge Low Low High Low
Capillary Block Low Low High Low
Less Air Flow on Evaporator (Indoor Unit) Low Low Low Low
Less Air Flow on Condenser (Outdoor Unit) High High High High
Dirty Condenser (Outdoor Unit) High High High High
Low Ambient Temperature Low Low Low Low
High Ambient Temperature High High High High
Insuffient Compressor Low High High Low

Insulation Thickness

Refrigerant Pipe Insulation Drain Pipe Insulation
22.22mm To 28.58mm 19mm 25mm / 32mm /40mm 6mm
12.7mm To 19.05mm 13mm / 19mm
6.35mm To 9.2mm 9mm / 13mm

 Referent Pipe Insulation

Pipe Pipe size Insulation Type (EPDM or NBR)
Standard conditions 86°F (30°C), < 85% High humidity conditions(a) 86°F (30°C), >85%
Liquid Pipe 1/4″ (6.35 mm)  To 3/8″ (9.52 mm) 3/8″ (9 mm) 3/8″ (9 mm)
1/2″ (12.70 mm)  To  2″ (50.80 mm) 1/2″ (13 mm) 1/2″ (13 mm)
Vapor Pipe 1/4″ (6.35 mm) To 7/8″ (22.23)  1/2″ (13 mm) 3/4″ (19 mm)

The distance between the supports of the copper pipes.

Diameter Distance (m)
 ≤ 20 mm 1 Meter
20 To 40 mm 1.5 Meter
 ≥ 40 mm 2 Meter

The permitted length and drop difference

Pipe length Max. pipe length <= 240 Meter
Equivalent length from the first branch to the farthest indoor unit <= 40 Meter
Drop height Drop height between indoor unit and outdoor unit <= 110 Meter
Drop height between indoor units <= 30 Meter

Factory Fabricated

Duct Size Gauge of GI sheet
1 – 900 mm 26
901 -1200 mm 24
1201 -1800 mm 22
1801 – 2100 mm 20
2101 – above 18

Site   Fabricated

Duct Size Gauge of GI sheet
Upto 750mm 24
750mm- 1500 mm 22
1510 mm- 2250 mm 20
above 2250 mm 18

Horizontal Ductwork

Ducts Size Maximum Spacing
Area (m2) Diameter
less than 0.4 less than 125 mm 2.5 Meter
0.4 to 1 125 to 1000 mm 2 Meter
more than 1 more than 1000 mm 1.2 Meter

Vertical Ductwork

Ducts Type Maximum Spacing (Meter)
round 3.6 Meter
rectangular 3 Meter

Rectangular Duct Sheet Thickness as per CPWD

Longest side (mm) Minimum sheet thickness
Galvanized Sheet Steel (GSS) IS: 277  For Aluminum IS:737
750 mm and below 0.63mm (22 Gauge) 0.8mm  (20 Gauge)
751 mm to 1500 mm 0.8mm  (20 Gauge) 1mm  (18 Gauge)
1501 mm to 2250 mm 1mm  (18 Gauge) 1.5 mm (15 Gauge)
2251 mm & above 1.25mm   (16 Gauge) 1.8 (13 Gauge)

Round Duct Sheet Thickness as per CPWD

Longest side (mm) Minimum sheet thickness
Galvanized Sheet Steel (GSS) IS: 277  For Aluminum IS:737
150 mm to 500 mm 0.63mm (22 Gauge) 0.8mm  (20 Gauge)
501 mm to 750 mm 0.8mm  (20 Gauge) 1mm  (18 Gauge)
751 mm to 1000 mm 0.8mm  (20 Gauge) 1mm  (18 Gauge)
1001 mm to 1250 mm 1mm  (18 Gauge) 1.5 mm (15 Gauge)
1251 mm and above 1.25mm   (16 Gauge) 1.8 (13 Gauge)

DUCT Support OR Gripple Wire Support

Duct Size (mm)  Spacing (M)  Size of MS Angle (mm x mm) Size of Rod Dia (mm)
Up to 750 2.4 32x32x3 8
 751 to 1000 2 40x40x5 10
1000 to 1500 2 40x40x5 10
1501 to 2250 2  50x50x6 12
2251 to above 2  50x50x6 12

Round Duct Support

Round Duct Size (mm)  Spacing of Supports (m) Size of M.S. Angle (mm) Dia. of Hanger Rod (mm)
 Up to 500 1.5 40 x 40 x 6 12
 501 to 1200 1.5 40 x 40 x 6 12
1201 to 2250 1.5  50 x 50 x 6 15

Normal Ducting:

Larger duct-dimension  Spacing of Supports (m)  Sheet thickness, SWG (mm)
Up to 750 mm 1.5 To 2 2 24 G (0.63 mm) (25×25 GI flanges acceptable)
751 to 1500 mm 1.5 To 2 22 G (0.80 mm) (25x25x3 MS flanges  up to 1000mm; 40x40x5 MS flanges beyond 1000mm)
1501 mm to 2250 mm 1.5 To 2  20 G (1.00 mm) (40x40x5 MS flanges)
Above 2250 mm 1.5 To 2  18 G (1.20 mm) (50x50x6 MS flanges)

Supporting details for Low-Pressure system

LARGER SIDE OF DUCT mm SUPPORTING
ANGLE mm
VERTICAL ROD
DIAMETER mm
MAXIMUM
SPACING BETWEEN
SUPPORTS mm
Upto 900 40x40x6 10 3000
901 to 1500 50x50x6 10 3000
1501 to 2400 50x50x6 10 2400
2401 and above  65x65x6 12 2400

Supporting details for Round Duct

DUCT DIAMETER mm STRAP ROD
No WIDTH mm THICKNESS G No DIAMETER mm
Upto 600 1 25 22 1 7
601 to 900 1 25 20 1 10
901 to 1250 2 25 20 2 10
1251 t o1500 2 25 18 2 10
1501 to 2100 2 25 18 2 10

 Diffuser size

Area   Ceiling Height  Diffuser size(dia.)
Up to 12 sqmm 2.4 – 2.7m 200mm
Up to 12 sqmm 3m   250mm
Up to 20 sqmm 2.4m – 2.7m   250mm
Up to 20 sqmm 3m   300mm
Over 20 sqmm multiple diffusers

Additional refrigerant charged volume

Liquid pipe Size R410A (kg/m)
6.4 mm 0.022
9.5 mm 0.057
12.7 mm 0.11
15.9 mm 0.18
19.1 mm 0.26
22.2 mm 0.37
25.4 mm 0.45

Drain Pipe Capacity

Condensate water volume : V (L/h)=Indoor Unit (HP)x2  I.D (mm)  Thickness (mm)
V ≤ 14 Φ 25 3
14 V ≤ 88 Φ 30 3.5
88 V ≤ 175 Φ 40 4
175 V ≤ 334 Φ 50 4.5
334 V Φ 80 6
*If Slop is <1% than select next higher Size of Drain Pipe

How to Design Efficient Street Lighting-Part-4


(F) Lighting Pollutions

  • Light pollution is an unwanted consequence of outdoor lighting and includes such effects as sky glow, light trespass, and glare. 
  • 30 to 50% of all light pollution is produced by roadway lighting that shines wasted light up and off target.

(1) Glare:

  • Glare is the condition of vision in which there is discomfort or a reduction in the ability to see significant objects. Glare affects human vision and it is subdivided into four components, Disability Glare, Discomfort Glare, Direct Glare and Indirect Glare.
  • By origin
  1. Direct Glare
  2. Indirect (reflected) Glare
  • By effect on people
  1. Disability Glare
  2. Discomfort Glare
  • Disability glare:
  • Disability glare is the glare that results in reduced visual performance and visibility.
  • Since disability glare reduces the ability to perceive small contrasts.
  • It can impair important visual tasks in traffic such as detecting critical objects, controlling headlights, and evaluating critical encounters, making glare a potential danger for road users.
  • LED light sources can provide very high luminance lev­els which may cause glare. For this reason, LED lamps are commonly equipped with diffusers to reduce this luminance.
  • Disability glare may vary for dif­ferent individuals and it can be calculated objectively.
  • In a particu­lar illuminated environment, the human eye will be able to detect differences in luminance down to a certain threshold. This threshold can be compared for a situa­tion in the same environment when a source of glare is added. By comparing these thresholds, the threshold increment can be derived.
  • Discomfort glare:
  • Discomfort glare is the glare producing discomfort. It does not necessarily interfere with visual performance or visibility.
  • As vertical light angles increase, discomforting glare also increases
  • Discomfort glare, on the other hand, is a subjective phenomenon and there is no method for its Rating.
  • Although the 9-point De Boer scale (ranging from “1” for “unbearable” to “9” for “unno­ticeable”) is the most widely used in the field of auto­motive and public lighting.
  • Direct Glare:
  • Direct glare is caused by excessive light entering the eye from a bright light source. The potential for direct glare exists anytime one can see a light source. With direct glare, the eye has a harder time seeing contrast and details.
  • A system designed solely on lighting levels, tends to aim more light at higher viewing angles, thus producing more potential for glare.
  • Exposed bright light source, for example a dropped lens cobra head or floodlight causes of direct glare.
  • Direct glare can be minimized with careful equipment selection as well as placement.

  • Figure illustrates two examples of exterior lighting that results in glare. 

  •  Fig shows how full cutoff luminaries (Shielded Luminaires) can minimize this direct glare. In exterior applications, use fully shielded luminaires that directs light downwards towards the ground.
  • Indirect Glare:
  • Indirect glare is caused by light that is reflected to the eye from surfaces that are in the field of view – often in the task area.
  • Indirect Glare can be minimized with the type and layout of lighting equipment. Direct the light away from the observer with the use of low glare, fully shielded luminaries.
  • As the uniformity ratio increases (poor uniformity), object details become harder to see.
  • For roadway lighting, good uniformity shows evenly lighted pavement. However, to meet small target visibility criteria, a non uniform roadway surface may be better.
  • There should be a balance between uniform perception and detecting objects on the road. Also, emphasis is put on horizontal surface uniformity. In reality, vertical surfaces may require more lighting in order to improve guidance.
  • How to Reduce Glare:
  • Glare and light trespass are more concern when installing floodlights.
  • Use shielded Light should be use to reduce Glare.
  • Higher mounting heights can more effective in controlling spill light, because floodlights with a more controlled light distribution (i.e., narrower beam) may be used, and the floodlights may be aimed in a more downward direction, making it easier to confine the light to the design area.
  • Lower mounting heights increase the spill light beyond the property boundaries. To illuminate the space satisfactorily, it is often necessary to use floodlights with a broader beam and to aim the floodlights in directions closer to the horizontal than would occur when using higher mounting heights.
  • Lower mounting heights make bright parts of the floodlights more visible from positions outside the property boundary, which can increase glare.

(2) Sky glow:

  • Sky Glow is brightening of the night sky caused by outdoor lighting.
  • Light that is emitted directly upward by luminaries or reflected from the ground is scattered by dust and gas molecules in the atmosphere, producing a luminous background. It has the effect of reducing one’s ability to view the stars in Night. 

  • How to Reduce Sky Glow
  • While it is difficult to accurately model sky glow, at this point it is presumed that the most important factors are light output and lamp spectral characteristics, light distribution from the luminaire, reflected light from the ground, and aerosol particle distribution in the atmosphere.
  • If the quantity of light going into the sky is reduced, then sky glow is reduced. Thus, to reduce sky glow by
  • By using full cutoff luminaires to minimize the amount of light emitted upward directly from the luminaire.
  • Reduce Lighting Level.
  • Make practice to Turn off unneeded lights
  • Limited Lighting hours in outdoor sales areas, parking areas, and signages
  • Installing Low-Pressure Sodium light sources, which allow astronomers to filter the line spectra from telescopic images.

 (3) Light Trespass:

  • Light trespass is condition when spill (Unwanted or Unneeded) light from a streetlight or floodlight enters a window and illuminates an indoor area.
  • How to Reduce Trespass
  • Select luminaries, locations, and orientations to minimize spill light onto adjacent properties.
  • Use well-shielded luminaries.
  • Keep floodlight aiming angles low so that the entire beam falls within the intended lighted area.

Difference between full cutoffs and fully shielded:

  • The full cutoff has is luminaries that have no direct up light (no light emitted above horizontal) and 10% of light intensity between 80° and 90°.
  • The term full cutoff is often substituted for the term fully shielded.
  • The both terms are not equivalent. Fully shielded luminaires emit no direct up light, but have no limitation on the intensity in the region between 80° and 90°
  • Luminaires that are full cutoff, cutoff, semi cutoff, and non cutoff , may also qualify as fully shielded.

  • There is also a confusing assumption that a luminaire with a flat lens qualifies as a full cutoff luminaries. While this may be true or not in some Lighting Fixtures case.

  • Fully shielded means, a lighting fixture constructed in such a manner that the bulb should be fully recessed into Fixture so that all light is directed downward below the horizontal.
  • The fixture is angled so the lamp is not visible below the barrier (no light visible below the horizontal angle).

(G) Selection of Luminas:

(1) Types of Lighting Source

  • Street Lights are mostly Low-pressure sodium (LPS), High-pressure sodium (HPS), Metal halide and Light emitting diodes (LED).
  • LPS is very energy efficient but emits only a narrow spectrum of pumpkin-colored light that some find to be undesirable.
  • LPS is an excellent choice for lighting near astronomical observatories and in some environmentally sensitive areas.
  • HPS is commonly used for street lighting in many cities. Although it still emits an orange-colored light, its coloring is more “true to life” than that of LPS.
  • Where it’s necessary to use white light, there are metal halide and LEDs.

  • High-pressure sodium lamps should be used for expressways, main roads, secondary roads and branch roads.
  • Low-power metal halide lamps should be used in mixed traffic roads for motor vehicles and pedestrians in residential areas.
  • Metal halide lamps can be used for motor vehicle traffic, such as city centers and commercial centers, which require high color identification.
  • Metal halide lamps, CFL lamps are used at Pedestrian streets in industrial areas, sidewalks in residential areas, and sidewalks on both sides of motorway traffic.
  • LED streetlights are more durable, longer lasting, efficiency, dimmable capacity and cost effective than traditional lights.
  • LED also enhances public safety by delivering superior visible light while providing the environmental advantage of using less energy.

(2) Color Rendering Index (CRI):

  • CRI Measures the ability of the artificial light to show or reproduce the colors of the road or objects on the road, relative to a natural light source.
  • The natural light source (the sun) has CRI of 100. The higher
  • This index the better the visibility will be. For all types of road CRI ≥ 70 is recommended.
  • Efficacy
  • At the low end LED efficacy starts at 70 lumens per watt (lm/W) and reaches as high as 150 lm/W.
  • While the mean efficacy for outdoor area fixtures is slightly lower than common indoor fixtures such as troffers and linear lighting about 100 lm/W for area lights compared to about 110 lm/W for troffers and linear fixtures this difference is not significant. It may be the result of outdoor area lights requiring more precise luminous intensity distributions and other factors unique to outdoor lighting.

(3) Fixture Protection:

  • When using sealed road lighting, the protection level of the light source cavity should not be lower than IP54.
  • For roads and places with dangerous environmental pollution and heavy maintenance, the protection level of the light source cavity should not be lower than IP65.
  • The degree of protection of the lamp electrical appliance cavity should not be lesser than IP43.
  • Lamps with excellent corrosion resistance should be used in areas or places with high levels of corrosive gases such as acid and alkali in the air.

(H) Effective Road Lighting:

  • Sufficient illumination.
  • Good uniformity.
  • No Glare.
  • Low consumption.
  • No Color Temperature abnormalities
  • No Zebra effect
  • Shielded lighting to ensure light is pointed downwards
  • Completely uniform illuminance.
  • No requirement for over lighting to obtain sufficient average illumination.
  • Absence of glare.
  • Absence of low angle radiation that causes sky glow.
  • Control of light trespass.
  • High redundancy.

Effective Road Lighting 

Features

Benefits

Proper pole height & spacing

 Provide uniform light distribution

Proper Luminaire aesthetics

 Blends in with the surroundings
Good maintenance

Reduce problems in lightning

High lamp efficiency

 Minimize energy cost

Life of Luminaire

Reduce lamp replacement cost
Good color rendering

 Helps object appear more natural

Proper light distribution

 Provide required light on roads

Cost effectiveness

 Lowers operating cost

Minimizing light pollution & glare

 Reduce energy use

Effective Energy-efficient Street Lighting Systems (NYSERDA, 2002)

Features

Benefits

Proper pole height and spacing Provides uniform light distribution, which improves appearance for safety and security Meets recommended light levels Minimizes the number of poles, reducing energy and maintenance costs
Proper luminaire aesthetics Blends in with the surroundings
High lamp efficacy and Luminaire efficiency Minimizes Energy cost
Life of the luminaire and other components Reduces lamp replacement costs
Cost effectiveness Lowers operating cost
High Lumen Maintenance Reduces lamp replacement costs
Good color rendering Helps object appear more natural and pleasing to the public Allows better recognition of the environment, improves security
Short lamp Re strike Allows the lamp to quickly come back after a power interruption
Proper light distribution Provides required light on the roads and walkways
Proper Cutoff Provides adequate optical control to minimize light pollution
Minimizing light pollution and Glare Reduces energy use
Automatic Shutoff Saves energy and maintenance costs by turning lamps off when not needed

Minimum Value of Street Light Designing

Descriptions

Min Value

Watt

400
Lumens Per Watt

80 To 140

Voltage

230Volt
Frequency

50 To 60Hz

Power Factor

  More than 95

THD

 < 20%
Life Hours

70,000 hours

Color Temperature

4000K  To  5000K

CRI

More than 75

Beam Angle / Beam Pattern

 Type 2,3,4,5
Operating Temperature

(-)25°C To (+)50°C

Working Humidity

10% To 90% RH
IP Rating

 IP67

Dimmable

0-10V

Optic Lens Material

High Polycarbonate (PMMA)
Forward Current

>600mA

Housing

IP65 – Aluminum Alloy and PC Lens

Dimension

 18.23″ X 13.58″ X 4.57″

Weight

 15.30 lbs – 34.39 lbs
Warranty

10 Years

 

 

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