Method of Statement for Fire Fighting Works (Part-2)

(5) Vertical risers

  • Vertical risers shall be parallel to walls and column lines and shall be straight and in plumb. Risers passing from floor to floor shall be supported at each floor by MS angle with clamp as per specification of pipe support.
  • The space in the floor cut outs around the pipes work may be closed using cement concrete (1:2:4 mix) or steel sheet, from the fire safety considerations, taking care to see that a small annular space is left around the pipes to prevent transmission of vibration to the structure.
  • Riser shall have suitable supports at the lowest point.

(6) Sprinkler Heads & Accessories

  • Installation of sprinkler heads will be done after pipe work flushing is completed.
  • Apply the PTFE tape only to the male portion of the sprinkler and install the upright sprinkler head using the wrench provided by the manufacturer, and in such a way that the arms are parallel to the branch pipe. Maintain a clearance of 1” between the deflector of upright sprinkler and ceiling. Ensure that sprinkler heads have the correct finish and temperature rating.
  • For fixing sprinkler heads, 15 mm. dia. M.S. Socket is to be screwed to range pipes at the locations as’ per drawings. Dead plug shall be fixed in the socket.
  • If sprinkler head is to be provided away from range pipe, M.S. Pipe nipple of suitable size be used to extend the sprinkler head and socket is welded at desired location.
  • During occupation of the building, sprinkler heads shall be provided in place of dead plugs. Teflon tape shall be used on threaded portion.

(7) Fire Hose Reel / Fire Hose Cabinets

  • Check cabinets are approved size and dimension. Inspect for signs of damage.

  • Locate exact location of these Cabinets as per approved shop drawings and with careful measure of elevation and plumb.

  • Fix cabinet using recommended anchor and bolts. Proceed with installation of accessories, lock shield valve, landing valves, etc. taking in consideration of approval for these devices.
  • Prior to the installation Foreman will read, understand and strictly follow the manufacturer’s instructions.
  • Examine the location of the hose reel cabinets and ensure that opening is sufficient for fixing all equipment and the mounting height of the hose valve and hose racks is as per the approved shop drawings and to the requirements. Hose reel, hose valves and fire extinguishers are of approved type and have the correct rating.
  • The cabinet (without the equipment) will be installed where applicable. Branches to the hose rack (reel) / hose valve will be installed on site to ensure actual entry point to the cabinet. Location of Pipe sleeves shall be as per approved drawings.
  • Hose reel & valve will be installed as per the manufacturer’s instructions at the correct mounting height.
  • Keep fire extinguisher inside the cabinet along with the hose rack. Ensure that the top of the wall mounted extinguisher do not exceed from the levels as per approved drawing and specification.

(8) Drain Piping of the System:

  • Fittings will be of the eccentric pattern to ensure proper drainage and the elimination of air pockets wherever necessary.
  • In Sprinkler Network at far end Drain Pipe shall be provided on last Sprinkler to remove Air from Sprinkler Network.

(9) Sleeves

  • The branch lines will be hanged to the proper level and will be connected to the cross main. Where piping is embedded or passing through masonry or concrete, sleeves will be provided as per specification mostly of MS or GI material.
  • Pipe sleeves of diameter larger than the pipe by least 50 mm shall be provided wherever pipes pass through walls and the annular spaces shall be filled with felt and finished with retaining rings.

(10) Sealant

  • After the removal of the concrete forms and installation of the pipeline, the annular space between the sleeve and the pipe shall be filled with caulking material leaving enough space at both ends of the sleeve for sealing.

(11) Under Ground Pipe

  • Where mild steel pipes are to be buried under ground the same shall be treated anti corrosion treatment. The top of the pipes shall be not less than 100 cm below the ground level.
  • Where this is not practicable, permission of the Engineer-in-charge shall be obtained for burying the pipes at lesser depth.
  • After the pipes have been laid, the trench shall be refilled with the excavated soil and rammed and any extra soil shall be removed from the site of work by the contractor.
  • Underground pipe shall be laid at least 1 meter away from the face of the building preferably along the roads and foot paths.
  • As far as possible lying of pipes under road, pavement and large open spaces shall be avoided.
  • To facilitate detection of leak and isolation of defective portion of pipe, valves shall be provided in underground pipe at suitable locations.
  • As far as possible such valves shall be provided over ground or at Basement. If the valves are to be provided below ground, suitable masonry chamber with cover plate shall be provided.
  • Locations where vehicles can pass shall be avoided for provision of valve below ground

(12) Anti-Corrosive Protection on Under Ground Pipe

  • Corrosion protection tape shall be wrapped on M. S. Pipes to be buried in ground.
  • 2 No’s of corrosion protection tape minimum 4 mm thick shall comprise of coal tar/asphalt component supported on fabric of organic or inorganic fiber and conform to requirement of IS 10221 Code of practice for coating and wrapping of underground mild steel pipe line.
  • Before application of corrosion protection tape all foreign matter on pipe shall be removed with the help of wire brush and suitable primer shall be applied over the pipe thereafter.
  • The primer shall be allowed to dry until the solvent evaporates and the surface becomes tacky.
  • Both primer and tape shall be furnished by the same manufacturer. Corrosion protection tape shall then be wound around the pipe in spiral fashion and bounded completely to the pipe.
  • There shall be no air pocket or bubble beneath the tape. The overlaps shall be 15 mm and 250 mm shall be left uncoated on either end of pipe to permit installation and welding.
  • This area shall be coated after the pipe line is installed. The tapes shall be wrapped in accordance with the manufacturer’s recommendations.
  • If application is done in cold weather, the surface of the pipe shall be pre- heated until it is warm to touch and traces of moisture are removed and then primer shall be applied and allowed to dry.

Flushing, Cleaning of Piping and Equipment:

  • After piping is erected, all piping systems including main header line and branch line will be cleaned to remove all mill, welding scale, oil, corrosion, and other construction debris. 
  • Prior to hydraulic testing, all pipe work systems including valves, strainers and fittings will be washed thoroughly. Any washing of the piping systems will be carefully carried out where there are isolation valves or equipment are employing.
  • Any stoppage due to foreign matter or air lock which is found to impede the flow of fluid will be removed, either before or after the systems are in operation.
  • Do not operate pumps or equipment until debris has been removed from the respective system has been flushed out.
  • Flushing of the system can be done from a pumping source with minimum flow rate to provide a velocity of 3 m/ sec.
  • Flush the piping system until all debris is removed and clean water comes out.
  • Automatic devices which can become clogged during the cleaning process will be disconnected and will not be connected permanently until the cleaning process is complete.
  • Enough draining points will be left for this purpose. These points will be the lowest point of the area/zone and the water supply point.


  • All pipes & fittings above ground and in exposed locations shall be painted with two coat of zinc chromate primer and two or more coats of synthetic enamel of fire red color paint.
  • Clean the MS / GI Pipe
  • Clean the black pipe with cotton rag to remove any dust or grease on the pipes before painting.
  • Fabrication of Pipe:
  • After Cleaning, fabrication work of Sprinkler network shall be completed on ground level.
  • Paint the Pipe with 1st Coat Red Oxide (Before Fabrication)
  • After Fabrication of MS Pipe, paint the black pipes with one coat of approved Red-oxide Primer will be applied as per Manufacture’s film thickness or Microns measured as per Sample paint.
  • Please ensure both sides (top & bottom) are painted evenly.
  • Put the painted pipes in a good ventilation condition for 24 hours for the paint dry.
  • Paint the Pipe with 2nd Coat Red Oxide
  • After completion of 1st Coat apply, 2nd coat of Red oxide shall be applied of as per Manufacture’s film thickness or Microns measured as per Sample paint.
  • Put the painted pipes in a good ventilation condition for 24 hours for the paint dry.
  • Paint the Pipe with 1st Coat of Enamel Paint:
  • After drying, red oxide, 1st Coat of Enamel Paint will be applied on Pipe with as per Manufacture’s film thickness or Microns measured as per Sample paint.
  • Please ensure both sides (top & bottom) are painted evenly.
  • Put the painted pipes in a good ventilation condition for 24 hours for the paint dry.
  • Install the Pipe
  • After the 1st Coat of Enamel Paint dry, install the pipes.
  • Paint the Pipe with 2nd Coat of Enamel Paint:
  • After Completion of Hydro Test, 2nd Coat of Enamel Paint of Approved make of as per Manufacture’s film thickness or Microns measured as per Sample paint.
  • Please ensure both sides (top & bottom) are painted evenly.

Testing of the System:

  1. Initial Pressure Testing (24 Hour Test)
  •  After completion of the work, all valves/ fittings shall be installed in position and entire system shall be tested for 24 hours at a pressure of 10 Kg/cm2 to 15 kg/ cm2.
  • Plug all the openings
  • Close all the drain valves.
  • Fill complete pipeline with water avoiding any air column. (For this purpose keep the drain valve at the highest elevation slightly open, while filling water when line is completely filled with water close the valve)
  • By a pressure pump pressurize the line to an intermediate pressure of 10 Kg/cm2 to 15 kg/ cm2. Wait for 24 Hours.
  • Check all major joints for any visible leak.
  • The drop of pressure up to 0.5 kg/cm2 shall be accepted.
  1. Hydrostatic Testing of Pipe Work
  • Make available a highlighted drawing of area intended for hydrostatic pressure testing. Indicate on the drawing the location of vent/drain valve, plugged connections and water pressure pump connection.
  • Make sure the test witness timing and pressure duration are agreed by the client/consultant.
  • Place safety warnings at all points where personnel may pass through within the vicinity of testing.
  • Make sure that all equipment item such as sprinklers; valves etc. are subjected to the pressure test.
  • Attach the pressure pump to the desired location through an isolation valve, by pass valve and calibrated pressure gauge to indicate the pressure on the pipe work.
  • The entire pipe work shall be hydrostatically tested for not less than 2 hours at 15 bars (or 1.5 times the working) pressure without leak.
  • Physically check and ensure that all pipes undergoing test is strongly supported and addition of pipe work will not introduce undue stress on any support.
  • Make sure that all pipe works are suitably plugged.
  • Connect a calibrated and approved pressure gauge and fix an isolation valve just below the pressure gauge.
  • Apply pressure gradually until it reaches the test pressure. The test pressure will be as per agreed terms and as per requirements.
  • All piping shall be tested to hydrostatic test pressure of at least the 1.5 times of operating pressure, but not less than 15 kg./ For a period not less than 24 hours. All leaks and defects in joints revealed during the testing shall be rectified to the satisfaction of the Engineer-in-Charge.
  • Piping repaired subsequent to the above pressure test shall be re-tested in the same manner.
  1. Final Testing (Automation of the System)
  •  After completion of Hydro Test, all operation checks shall be carried out for automatic operation of the systems. For this purpose, landing valves may be opens at different locations. The exercise shall be repeated couple of times to ensure trouble free operation of the system.
  • Flow Test: The design flow of pumps shall be checked. The pump shall be operated after opening a number of landing valves at different locations. Design pressure is be maintained in the pump house. Water discharge is to be
  • Measured by drop in level in UG tank for a certain period. All pumps shall be tested one by one. The flow rate shall be not less than as specified while maintaining the design pressure in pump house.

Pipe Identification Installation:

  • After the pipe layout hydrostatically tested and finally painted, install pipe identification as per Site Requirements.
  • Background Color –Red.
  • Letter Color –White.
  • Lettering Size –as per Size of Pipe or Equipment.
  • Flow –Direction Arrows –integral with piping-system


  • Project Specification.
  • Indian Standard.
  • BS Code.
  • Local Fire Authority Regulations.
  • NFPA (National Fire Protection Association) Code.
  • NBC Code.


Method of Statement for Fire Fighting Works (Part-1)


This method describes the detailed procedure for installation and Testing of Wet Raiser Fire Protection System, Pipes, Sprinkler, Fire Pumps, Valves and Fire Fighting Accessories as per the standard Practice and Codes.

General Equipment & Tools:

The equipment that will be engaged for Installation of Fire Fighting works will be

  • Tool Box
  • Welding Machine
  • Drilling Machine with various Bits
  • Grinding Machine
  • Cutting Machine
  • Threading Machine
  • Chain Block
  • Pipe Wrench
  • Hand Tools-gloves.
  • Hammer
  • Portable Lights
  • Manual Excavation Tools
  • Removable Barricades
  • Scaffolding / Mobile scaffold
  • Ladder
  • Spirit Level
  • Screwdriver, Pliers, Spanner.
  • Marker
  • Pressure gauge
  • Level gauge / Spirit level.
  • Measuring tape
  • Pressure test pump.

Storage & Material Handling:

  • The storage area must be free from dust and the materials should be stacked in proper manner to avoid any damages.
  • The Material shall be stored in designated area of the Store to protect the M.S Pipe and Other Fire Fighting Accessories against effects of weather and environment.
  • The material shall be transported in their original packing to Site location.
  • The pipes will be stacked in the site store on a proper stand on wooden loft on a flat surface at a height not exceeding 1.7m. From the bottom layer.
  • All open ends of pipes will be covered to protect from foreign matter, dirt/debris
  • Fittings will be separately packed and stored as per the sizes required for the project.
  • Chemicals must be stored in well ventilated location and away from direct sunlight.

Inspection of Materials: 

  • Inspection of Pipe / Valve / Flanges:
  • Check Type of Material ,Size of Material , Make of Material.
  • Chemicals such as paints, primer and thinner, check their expiration date before receiving.
  • Physical Damages Inspection:
  • In case of any damages observed during inspection, the concern report will be issued and Material shall be returned to the supplier for replacement.

Installation Procedure:

(1) Pipe Hanger / Support Installations

  • Piping Route will be the as per most advantageous manner possible with respect to headroom, valve access, opening and equipment clearance, and clearance for other work.
  • The Line layout should be verified from Site in charge.
  • After marking the pipe routes, the anchoring points will be drilled according to the required support spacing as shown on the approved shop drawings.
Pipe Diameter (mm) Maximum Hanger Spacing (mm) Rod Size (mm)
25 2000 8
32 2500 8
40 2500 8
50 2500 8
65 2500 10
80 2500 10
100 * 2500 * 12 *
150 * 3000 * 16 *
200 * 3000 * 16 *
 * As per Site Requirement Fabrication Support may be used.
  • Mark out the location of hanger thread rods for pipe installation as per the approved construction drawing.
  • Fasteners and fully threaded rods shall be used for installing the pipe supports. The sizes of pipe supports and installation shall be in accordance with manufacturer’s recommendations.
  • For Single pipes of size 100 mm and above, with the prior approval 50xx50xx6 mm MS Angle iron and for Double Pipe 75x75x6mm with U Clamp with Fastener may be used for Supporting horizontal Pipe from ceiling.
  • Drill the marked position for hangers and supports by using the drill bit of appropriate size.
  • Fix the unfix anchor at drilled position by gentle and uniformly hammering.
  • Fix the threaded rod of appropriate diameter and size & length in the anchor by twisting by turning.
  • After fixing the threaded rod, insert a washer of appropriate size in to the rod.
  • Finally fix the washer near to the slab by tightening a nut over it, this will improve the strength and load bearing capacity of threaded rod.
  • For installing pipes vertically or horizontally inside the building standard pipe supports of reputed make shall be used. Following supports shall be used.
  • Clevis Hangers or MS Chanel for horizontal supports to adjust varying heights.
  • The Pipe route should be min 500mm away from wall.
  • Supports will be arranged as near as possible to pipe joints and any change in direction.
  • Vertical Riser Support:
  • Risers shall be supported by pipe clamps or by hangers located on the horizontal connections within 24 inches (0.6 Meter) of the centerline of the riser.

(2) Pipe Welding / Fabrication:

  • Welding Machine:
  • Welding machines shall be in good working condition and shall have proper control for regulating current.
  • Location of welding machines and the distribution boards to be connected with them shall be verified by site electrical Team to avoid overloading of the distribution boards, cables and electrical power sources.
  • All welding Machine ,other Electrical Tools, the electric cables, distribution boards and connections for machines shall be carefully checked once a Month to maintained it in a good working condition.
  • Welding cables used shall have proper insulation throughout the length. The cables sh
  • all be carefully examined and repaired as necessary every day.
  • Welding Electrodes:
  • Electrodes used for welding should comply with IS:814, 1991.
  • Generally all welding shall be performed using Shielded metal arc welding (SMAW) process using cellulosed-coated electrode (E6013 type) for root run and subsequent passes
  • Storing of Welding Electrodes:
  • Welding electrodes shall be stored in indoors free from moisture.
  • Qualified and certified welders only shall do welding.
  • No welding shall be done if there is impingement of any rain, or high winds
  • Fabrication of Pipe (But Welding):
  • The welding of pipes in the field should comply with IS:816, 1969.
  • All pipes and fittings shall be cleaned of Dust, Mud from inside and outside before Welding.
  • All pipe, fittings shall be smooth, clean and free from blisters, loose mill scale, sand and dirt prior to the installation.
  1. Edge Preparation: Before welding, the ends shall be cleaned by wire brush, filing or grinding and making “V” on edge of both pipe.
  2. Welding of Root Run: Primary Welding shall be done by E6013, 2.5mm Welding Rod (90 to 90A, 18 to 25V) of approved make.
  3. Chipping and Cleaning of Root Run: Each weld- Root run shall be thoroughly cleaned to remove the slag, irregularities and any defects, before the next run is deposited.
  4. Final Welding Run: Final Welding shall be done by E6013, 3.5mm Welding Rod (80 to 140A, 20 to 25V) of approved make.
  5. Chipping and Cleaning of Final Run: Each Final weld shall be thoroughly cleaned to remove the slag, irregularities and any defect

(3) Pipe Installation:

  • Installation of pipe shall be co-ordinate with architectural, structural and MEP work for a fit for purpose installation. Any deviation shall be intimated to the engineer for approval.
  • Cut all pipes accurately to measurement determined at the site. After cutting the pipe, ream it and remove all burrs.
  • Run all piping as direct as possible, avoiding unnecessary offsets and conceal piping in finished rooms.
  • Install all piping close to walls, ceilings and columns so piping will occupy the minimum space but Proper space will be provided for covering and removal of pipe, special clearance, and for offsets and fittings.
  • Pipe work will be installed not closer than 200 mm to electrical conduits, lighting, and power cables.
  • Pipes will be spaced in ducts, ceilings, voids and plant areas, such as adequate access is permitted to any pipe for maintenance or removal without disturbance to the remaining pipe work and other services.
  • Pipes will not be solidly built into walls or plaster. Pipe joints will not be positioned within the thickness of walls, floors or in any other inaccessible position. Pipes passing through walls and floors will be sleeved.
  • Couplers, unions and fittings will be screwed up to the reduced depth of the thread, such that no more three-turns are showing when pulled up tight.
  • All pipes, valves and fittings and connected equipment will be thoroughly cleaned of rust, sand and dust, scale and other foreign matter before erection and before any initial fill water for hydraulic testing.
  • After completion of pipe end connection, fix / tight the support clamps properly to make the pipe straight and level as per the layout.
  • Check the levels of pipe work with spirit levels and measuring tape.
  • The Spacing of fire pipe supports for sprinkler / clevis hanger shall not be more than that specified below
Pipe Support Details
Nominal Pipes Diameter Spacing between supports Hanger rod diameter Hanging Strip Size(thickxwidh)
Up to 25 mm 2.00 meter 8 mm 1.5mmx25mm
32 to 50 mm 2.50 meter 8 mm 1.5mmx25mm
65 to 80 mm 2.50 meter 10 mm 2mmx30mm
100 mm * 2.50 meter * 12 mm * 2mmx30mm *
150 mm * 3.00 meter * 16 mm * 3mmx30mm *
200 mm & above * 3.00 meter * 16 mm * 3mmx30mm *
* As per Site Requirement Fabrication Support may be used.
  • All lines shall be suitably supported so as to provide rigidity and avoid vibrations.
  • Proper lines and levels shall be maintained while installing exposed pipes.
  • All lines less than 50 mm NB size can be socket welded to matching rating fittings.
  • All lines above 50mm NB size shall be butts welded with full penetration welds.
  • All bolts, nuts and washers used shall be of GI.
  • Extra supports shall be provided at the bends and at heavy fittings like valves to avoid undue stress on the pipes.
  • Open ends of piping shall be blocked as soon as the pipe is installed to avoid entrance of foreign matter.
  • Pipes must be of Heavy grade M.S. pipe conforming to IS 1239. The pipes, fittings and installation shall be hydraulically tested to a pressure of 15 Kg/ or 1.5 times the working pressure whichever is higher.

(4) Flanges:

  • Mild steel flanges shall be in accordance with Table – 17 of IS : 6392 i.e. “Plate Flanges for Welding” and flange thickness shall be as under. Gasket thickness shall not be less than 3 mm.
  • Check the flange size and specification according to pump size and valve size,
Flange  Details
Pipe Dia Flange Thickness No. of holes
200 mm. 24 mm. 12
150 mm and 125 mm 22 mm. 8
100 mm and 80 mm 20 mm. 8
65 mm. 18mm 4
40 mm and below. 16mm 4
  • All hardware items such as Nuts, Bolts, and Washers shall be of appropriate size.
  • Washers shall be used on both sides of the bolt.

Method for Installation of DB or Panel-(Part-2)


  • For performing this test, it is generally recommended to use a milliohm meter for continuity measurement.
  • It is recommended to perform these tests before connection starting so all isolating devices will be closed.
  • If cables are already connected, open the isolating devices before any test.
  • Disconnect the ground sensing device and the control cables.
  • Using a 1000 V DC megohmmeter, measure the insulation resistance after a one minute Electrification time between :
  • 1) Phase to Phase
  • 2) Phase to Neutral
  • 3) Phase to Ground
  • 4) Ground to Earth
  • Using a 500 V DC megohmmeter, measure the insulation resistance after a one minute electrification time between:
  • 1) Auxiliary circuit and ground.
  • Reconnect the cables after testing.
  • Control Wiring Electrical Tests for Switchgear and Switchboards
  • Perform insulation-resistance tests on control wiring with respect to ground. Apply 500 volts dc for 300-volt rated cable and 1000 volts dc for 600-volt rated cable for one minute each.
  • Important: Units with solid-state components could be damaged if not properly isolated (via removal of plugs and/or fuses) before applying test voltage. Be sure to follow all manufacturers’ recommendations when performing dielectric tests on solid state components
  • Minimum insulation-resistance values of control wiring should be comparable to previously obtained results but not less than two megohms.

Charging & Testing of Panel:

  •  Cable Terminations:
  • Identify cable to be laid and Cut the cable to required length.
  • Put temporary marker onto the cable.
  • Carefully pull (using suitable method) and lay the cable to its route
  • Make appropriate opening (Cut-out) in DB /PANEL for inserting the cable with a rubber gasket so that there will be no sharp edges and secure the wire insulation from damage.
  • Gland the cables using appropriate cable glands size.
  • Terminate cables inside enclosure by securing cables to switchboards with gland bracket; and enclosure with glanding plates or fabricated steel extension boxes.
  • Slice the cable and identify cores to be used. Installed the ferrule number and cable lug
  • Dressing the cable inside the panel and Secure the cables (if necessary) with cable ties or other suitable method
  • Install cable marker / tag as specified
  • Terminate the cable properly & as per termination schedule
  • Earth the glands to the equipment earth grid
  • After complete termination of wire/cable same DB compartment shall be cleaned and fixed door.
  • Earthing Connections:
  • The Panel Main earthing bar is to connected to earth electrode or earthing Grid by Suitable size of 2 No’s of Eathing Strip or Earthing Wire via testing joints.
  • Energize the Panel
  • Switch off All Switchgear of Panel.
  • Connect the incoming cables of Panel to the Power Supply Source.
  • Check healthy ness of Power Supply at incoming of Panel.
  • NO LOAD:
  • Measure input Voltage of Power Supply between Phase to Phase, between Phase and Neutral and between Neutral and Ground.
  • If measured incoming Voltage is within limit than Switch ON the Main Breaker of Panel.
  • Measure Voltage on Bus bar between Phase to Phase, between Phase and Neutral and between Neutral and Ground.
  • If measured Bus bar Voltage is within limit than Panel should operate on NO LOAD Condition for 5 minutes to observe any heating, sparking and performance of accessories of Panel.
  • After 5 minute, one by one Switch ON the all Circuit Breaker of Panel.
  • ON LOAD:
  • Measure Voltage on each outgoing feeder of panel between Phase to Phase, between Phase and Neutral and between Neutral and Ground.
  • If measured Voltage of outgoing feeders are in within limit than Panel should Energize for 2 hours and verify complete performance. Check for any unusual temperature rise in cables, terminals and protective devices.
  • Correct Phasing:
  • Check Phase Sequence of Power Supply at Outgoing Circuit of Panel.
  • If there is not correct phase sequence for three phase power supply, reverse one phase at incoming side of Panel.
  • Indicators
  • Check all Power Supply ON /OFF / TRIP indicator works properly.
  • If any associated converters check the indications to the corresponding output terminal block.
  • Under/Overvoltage Protection
  • Check the relay operation and adjust to the desired rating.
  • The protection information reports shall be checked up to the distribution board output terminal block.
  • Automatic Transfer Switches
  • Check mechanical and / or electrical interlocks.
  • With the both available supplies (Main Power & D.G Power) confirm the functional checks by presence of voltage, loss of supply, restoration of supply in manual and in automatic mode.
  • The both incoming supplies are readiness in the distribution board
  • Record The Test Data:

Floor Marking Near Electrical Panels:

  • Keep Space in Front of Electrical Panels Clear
  • The area in front of electrical panels must be kept clear and marking with effective floor marking taps.
  • While specific colors of floor marking tape are not required, it’s often recommended that employers select colors that indicate a hazard is present. Striped black and yellow floor marking tape often serves this purpose, as black and yellow are regularly used for hazard markings.
  • When the nominal voltage to ground for a piece of electrical equipment is 600 volts or less, the minimum depth of clear working space in front of the equipment must be 3 feet (in some circumstances, it must be larger). This distance applies to some situations involving voltages up to 2500 volts as well. 


Codes and Standards:

  • Panel shall comply with the latest Relevant Indian Standards and Electricity Rule and Regulations and shall be as per IS-13947-1993.
  • The general construction shall confirm to IS-8623-1977 (Part-1) for factory built assembled switchgear & control gear for voltage up to and including 1100 V AC.



Method for Installation of DB or Panel-(Part-1)


  • This method of statement describe the procedure for safely installation and testing of DB and LV Panel as per contract specification and as per the standard Practice and Code.

General Equipment & Tools:

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

Storage & Material Handling:.

  • Suitable lockable storage shall be made on Site.
  • The storage area must be free from dust and Water leakages / seepages.
  • The DB, Panel and Accessories shall be unloaded with care in designated area of the Store to avoid any damages and against the effects of weather or any construction activities of Site.
  • 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.
  • Materials shall be stored in a place free of water and adequately covered to avoid any kind of damages.
  • Proper protection should be given to the material by means of covering the material with Tarpaulin sheet etc.
  • If they are dispatch in packs or pallets, each pack of pallet shall be lifted individually with suitable lifting equipment.
  • The material shall be transported / Shifted in their original packing to Site location.

Inspection of Materials:

  • Inspection of Materials:
  • Check the reference of delivered material against approved submittal and purchase order.
  • Check The Material according to its Type, Size, Make
  • Physical Damages Inspection:
  • In case of any damages observed during inspection, the concern report will be issued and Material shall be returned to the supplier for replacement.

Sequence of Installation Works:

(1) Shifting of Panel on Site

  • Prior to commencement of Panel installation works, areas and access shall be checked and confirmed by safety officer, that they are in a suitable Condition for installation works.
  • Decide appropriate Size of Crain / Hydra according to weight of Panel.
  • Panel 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 panel is free from transportation damages
  • Check The shop drawings, Material submittals, Method statement, ITP & HIRA are approved,
  • Ensure all contents are available inside the panel.
  • Ensure control wiring identification shall be correctly done.
  • Megger shall be used having a valid calibration certificate.


(2) Installation of Panel:

  • Marking of Panel Position:
  • For floor mounted panel, the exact location of the panel and fixing holes to be marked on the concrete plinth for the installation.


  • Remove the Factory packing and ensure that the LT panel is free from transportation damages


  • Install the panel in proper alignment and fix properly.


  • To secure panel base to the floor using M12 anchor bolts.
  • Access around the panel to be checked for future maintenance as per regulations.
  • Ensure the services contains water is away from the panel or properly protected against any accidental leakages.
  • Incoming and outgoing cables shall be marked/identified as per approved shop drawing.
  • Mark the fixing position of the DB’s support as per approved shop drawing and coordinate with other equipment and services.
  • After marking are then drilled according to the selected sizes of anchor bolts to appropriate depth as per approved shop drawing.
  • Locknuts on the anchor bolts will ensure a permanent fixing of the DB support to the wall/slab.
  • After installation of DB supports, installing position of the DB as per approved shop drawing.
  • Ensure that painting of the wall is completed prior to marking and mounting of DB.
  • All DBs wall mounting and floor mounted arrangement will be in accordance with approved shop drawings and the approved material submittal.
  • If there is more than one DB to be installed at the same location, they shall be installed side by side and clearance shall be maintained as per approved shop drawing.
  • The height of Distribution Board shall be maintained as per approved shop drawing so that easy access for termination of cables and other maintenance work can be carried out.
  • Check the position according to the approved shop drawings.
  • Check & ensure adequate space is available for maintenance
  • After installation, the panel shall be properly cleaned and protected to prevent dust & contamination.
  • Before beginning installation in any area, examine all adjoining works in that area should be completed. Installation shall not proceed in that area until such conditions are corrected by the contractor.
  • Fix all equipment independently of wiring system. Use cadmium of zinc electroplated bolts, nuts, washers and screw.
  • Mount single DB at 1800mm from finish floor level to top of equipment, unless shown otherwise on drawing / schedules.
  • Ensures that clearance in front of switchgear is not less than 1m, or as indicated.
  • For flush installation, DB’s all conductors shall terminate behind the board in an adaptable box.
  • For surface mounting, trunking shall be fixed between the board and ceiling or floor level, or conduit run directly into Trunking which prevent correct installation of the Trunking lid.
  • The panel with plywood will be pushed towards the trolleys inside substation Room
  • When the panel reaches on the trolleys inside the substation room. Push the panel to the location where need to install .
  • To set up the chain block support to fix the chain block.
  • When the panel reaches the actual installed location, lifting-up of panel by using of chain block. Lift the panel on the panel base
  • If Panel is in section wise
  • Position the first section panel on the fixing channel & check the leveling by using the level bar & adjusting with liners.
  • To secure panel to the panel base using M12 anchor bolts.
  • To rack in the correct breaker & PT to the correct panel.
  • Proceed in the same manner for the second sections.
  • Position the second section next to the first panel.
  • Secure the second section to the panel base using two M12 anchor bolts
  • Interconnect & fasten the two section units together.
  • Proceed in the same manner for the other sections.

(3) Non Electrical checks before Charging Panel:

 (a) General Checking of Panel:

  • Confirm label/marking to ensure that is the Panel is correct according to the approved shop drawings.
  • All components (Circuit Breakers, Relays, Voltmeter and Ammeter) of the panel shall be verified against the approved panel / Technical drawing as per correct in Numbers, rating & size.
  • Ensure all contents are available inside DB.
  • Check that it is not possible to come into contact with energized equipment when working on the system.
  • If there are any Correction or modification than Check All internal connections/modification will be carried out by the Manufacturer.
  • Check the main bus bar and auxiliary circuits (control, monitoring, alarm, and fault) for continuity.
  • All breakers (incoming/outgoing) shall be in “OFF” position and to be locked to prevent mishandling

(b) Visual Checking of Panel:

  • Ensure the absence of all foreign bodies inside the switchboard.
  • Identifications labels of approved engraved type nameplate shall be fixed on DB.
  • Check the compliance with the protection index (leak tightness of the functional units, various sealing points, etc.).
  • Check the Continuity of grounding bus bar to the main earthing system.
  • Check that the panel hinged doors are connected to the frame by earthing braids.
  • Adequate earth continuity shall be made between the various components.
  • Check the door locks for correct operation
  • Check the connections for conformity with the reference drawings.
  • Check Continuity of Main, Auxiliary, Eathing and Neutral Busbar with respect to incomer and outgoing Circuits.
  • Check the connections for conformity with the reference drawings and their tightness.
  • Number terminals, cables and component parts to correspond with manufacturer have certified drawings.
  • Ensure that vents are clear and filters are in place. Screens covering ventilation openings should be in place to prevent entry of rodents or small animals.
  • Check the outer appearance (absence of any traces of shocks, peeling paint) -carry out any touch-ups if needed.

(c) Mechanical Checking of C.B:

  • Check for correct racking in and Out for circuit breaker and check :
  • That it is impossible to rack in a circuit breaker in the closed position.
  • That it is impossible to close a circuit breaker not correctly racked in.
  • That it is impossible to rack out a circuit breaker is in ON condition.

(d) Tightness of all Connection of Switchgear.

  • Fully tight all Bolted electrical connections of Electrical Switch gear of Panel.
  • Loose bolted electrical connections can lead to higher energy consumption and eventual equipment failure if not properly addressed.
  • Loose control, Power wires can lead to spark, over heat which turns in to catastrophic failure.
  • Check that all wiring connections are tight and that wiring is secure to prevent damage during routine operation of moving parts, especially when removing draw-out circuit breakers or opening and closing cubicle doors.
  • Gently tug on control wires to ensure a tight connection or use a screwdriver to gently verify torque on the connection. Infrared scans are also very effective for finding loose wires in control circuits.
  • Tighten all the connections as required

(d) General Wiring Checks for Switchgear

  • Wire inserted in the Panel will be cross-checked for existing circuit number done and final ferruling shall be done as approved shop drawing. 
  • Wire in Panel shall be used cable tie and dress with bunching of the phase-neutral and earth and lugged to the respective MCBs and Bus bar as per approved shop drawing.
  • Bunching shall be done as per phase separation respectively R, Y and B.

(e) Moving Parts and Interlock Checks for Switchgear

  • Confirm the correct operation and sequencing of electrical and mechanical interlock systems. Attempt closure on locked-open devices and attempt to open locked-closed devices.

(f) Lubrication of Switchgear and Switchboards

  • Check for appropriate lubrication on moving current-carrying parts and moving/sliding surfaces to keep everything operating smoothly. This includes hinges, locks, and latches.

(g) Insulators and Barrier Checks for Switchgear

  • Tracking is an electrical discharge phenomenon caused by electrical stress on insulation. This stress can occur phase-to-phase or phase-to-ground. Although tracking can occur internally in certain insulating materials, these materials as a rule are not used in medium- or high-voltage switchgear insulation. Tracking, when it occurs in switchgear assemblies, normally is found on insulation surfaces.
  • Electrical insulators should be inspected for evidence of physical damage or contaminated surfaces. Damage caused by electrical distress is normally evident on the surface of insulating members in the form of corona erosion or markings or tracking paths.
  • Inspect barrier and shutter assemblies for proper installation and operation. All active components should be exercised, mechanical indicating devices should be inspected for correct operation.

(h) Moisture and Corona Inspections for Switchgear and Switchboards

  • If corona occurs in switchgear assemblies, it is usually localized in thin air gaps that exist between a high-voltage bus bar and its adjacent insulation or between two adjacent insulating members. Corona might also form around bolt heads or other sharp projections that are not properly insulated or shielded. Corona in low-voltage switchgear is practically nonexistent.
  • Inspect for evidence of moisture or corona when performing maintenance inspections. On outdoor assemblies, roof or wall seams should be checked for evidence of leakage, and any leaking seams should be sealed with weatherproof caulk.

Quick Reference -Earthing

Hot dip galvanization. (IS 2629)


Minimum thickness:

Min. weight:

MS flats 5mm thick & over

75 microns (minimum)

610 gms. / sq. mtr.

MS flats under 5mm thickness

60 microns (minimum)

460 gms. / sq. mtr.

Pipes/ conduits with thickness  & over 5 mm

75 microns (minimum)

610 gms. / sq. mtr

Pipes/ conduits with thickness under 5mm

60 microns (minimum)

460 gms. / sq. mtr

GI Wire

20 Microns (Medium coated)

150 gms. / sq. mtr.



Size of Earthing Strip

Minimum Over Laping

























Size of Earthing Strip

Minimum Nut Bolt Required

Minimum Size of Nut Bolt


2 NO’S



2 NO’S



2 NO’S



2 NO’S



2 NO’S



4 NO’S



4 NO’S



4 NO’S



4 NO’S



4 NO’S



4 NO’S



Weight of G.I. wire  (Steel Tube India)

Gauge Gms.


Weight Kg / Meter.























Weight of G.I Flat Strip

Sizes in (HxW)

Kgs/Per meter


20×3 mm


Lighting Arrestor

20×6 mm


PLC Panel

25×3 mm



25×5 mm



25×6 mm


Control & Relay Panel

32×5 mm


Lighting Panel & Local Panel

32×6 mm


Distribution Board

40×3 mm


Motors 5.5kw-55Kw

40×5 mm



40×6 mm


HT switchgear, structures, cable trays & fence, rails, gate and steel column

50×3 mm


50×5 mm


50×6 mm


50×10 mm


Transformers Substations

62×6 mm


65×10 mm


75×10 mm


75×12 mm



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.


  • 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.


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


  • 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°


  • 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.


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


(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.


  • 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


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


4 To 500


501 To 1200


1021 To 3200


3201 To 10000




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

Mean coating thickness (minimum)µm

Mean coating

Steel > 6 mm





Steel > 3 mm to < 6 mm





Steel > 1.5 mm to < 3 mm





Steel < 1.5 mm





Casting > 6 mm





Castings < 6 mm





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)
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.


  • 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.

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