Method for Installation of Conceal & Surface Conduits (Part-2)


4.Filling Chasing Area:

  • All grooves, chases shall be properly filled and concreted and finished up to the wall surface before plastering of walls is taken up. The conduit boxes, accessories, joints, etc. shall be laid along with the conduits. The chases shall be sufficiently deep and properly filled with cement mortar.
  • Where conduits pass through expansion joints in the building, adequate expansion fittings or other approved services shall be used to take care of any relative movement. As far as possible, chasing of wall to embed the conduits to be avoided.
  • Chasing is filled by Cement mortar 1:5 ratio(1 portion of the cement+5 portion of sand) shall be used for patchwork in chased area and its surface is rough so main plaster will easily joint on chasing area.
  • Curing shall be carried out for a minimum of three days.
  • Make sure the conduits are not visible from outside their route which could lead to improper plastering.

5.Wire Mesh:

  • After chasing area is filled by mortar, Chicken (wire) mesh and GI nails shall be applied on chasing area to avoid hair crack in plaster.
  • Width of Chicken Mesh is slightly larger than chasing Area. After installation of Chicken mesh final Plaster should be done.
  • Make Sure that Nails for Wire Mesh should not damage the Buried PVC Conduit.

A

6.Surface Conducting:.                                                           

  • Take the approved Drawings of Electrical conduit Shop Drawing with section details, MEP coordination drawing with section details and Architectural Drawings.
  • Ensure that the civil people have finished block wall and Plastering with adequate curing and clearance is given to proceed for electrical works.
  • Check the required reference markings are available for FFL (finished floor levels).
  • All required materials shall be shifted and stored under safe custody near workplace on daily basis as per planned quantity.

1 ) Marking of Conduits:

  • Site Engineer will carry out a site survey where the PVC Conduit will be installed as per approved shop drawings.
  • Mark the exact position of the conduit route with the blue marker string and then install conduit saddles.
  • All runs must be installed as a complete system before any conductors are pulled into them. In other words, a run of conduit (to include conduit, fittings, and supports) must be complete before the conductors are installed.
  • A run of conduit should be as straight and direct as possible. When a number of conduit runs are to be installed parallel and next to each other, install them all at the same time.

2) Installation of Conduits:

(A) PVC Conduit and Accessories:

  • Conduits shall run vertically or horizontally only for surfaced run conduits.
  • Install the correct Type and size of the conduits as per approved Specification and drawing.
  • Conduit pipes shall be fixed by heavy gauge saddles, secured to suitable wood plugs or other approved plugs with screws in an approved manner at an interval of not more than 1 meter but on either side of the couplers or bends or similar fittings, saddles shall be fixed at a distance of 30cm from the center of such fittings.
  • The saddles should not be less than 19MM (width) of 24 gauge for conduits up to 25 mm dia and not less than 25mm (width) of 20 gauge for larger diameter conduits.
  • Where conduit pipes are to be laid along the trusses, steel joint etc. the same shall be secured by means of special clamps made of MS. Where as it is not possible to drill holes in the trusses members suitable clamps with bolts and nuts shall be used.

B

  • Where conduit pipes are to be laid above false ceiling, either conduit pipes shall be clamp to false ceiling frame work or suspended with suitable supports from the ceiling slab.
  • For conduit pipe run along with wall, the conduit pipe shall be clamped to wall above false ceiling in uniform pattern with special clamps if required to be approved by the Engineer-In-Charge at site.
  • Check to ensure no sharp edges within the conduit joints for surfaced conduit and to ensure proper bonding for all conduit joint for concealed PVC conduit by foreman / skill worker / sub-contractor.
  • All joints in PVC conduits, other than screwed joints, shall be cemented with a waterproof adhesive. This adhesive shall be as recommended by the conduit manufacturer.
  • All saddles, tubes and boxes must be in perfect alignment to avoid any appearance of warping when the installation is complete. Saddles should not be so tight as to prevent expansion of the conduit.
  • Power conduit and LV conduit need to be separate. Power, Lighting Circuit should be run in separate conduit than LV circuit (Data wire, Telephone wire, TV wire) conduit.
  • Conduits shall not be run closer than 15m to any steam or hot water pipes and shall be run underneath such pipes rather than over them.
  • Conduits should not also be run closer than 05m to any telephone, bell or other signaling circuit.
  • Particular care shall be taken to ensure that no grout or other foreign materials enters the conduit system through joints, or through surface openings.
  • All conduits shall be run as far as possible along the walls and ceiling and above false ceilings so as to be easily accessible for inspection if need be. While the Architects drawings indicate the distribution for light and power points
  • PVC conduits shall be ISI grade and it shall be rigid type.  Where conduits are laid in straight run, draw boxes shall be provided at intervals not exceeding 10 meters.  Between two consecutive draw boxes the right angle bends shall not exceed two in number.
  • Drawn-in boxes must be provided to give access to all conduit for the drawing-in or out of any cable after the installation is completed.
  • Terminations of PVC conduits into switch boxes, DBs, etc. shall be with adapters.  PVC conduits shall be fixed to accessories such as coupler, circular boxes, etc. with vinyl cement.

(B) GI / Steel Conduit and Accessories:

  • GI Conduiting layout complete with MEP coordination and Architectural Drawing complete with section details.
  • Check the route of GI Conduiting free from debris and no obstruction of any other activity.
  • Arrange scaffolding of sufficient height approved by HSE officer.
  • Mark the reference points on wall/ column as per civil architectural drawing.
  • Identify the circuit start point and end & mark GI Conduiting route as per approved drawings.
  • Prior to erection, all burrs and sharp edges shall be removed from the conduit together with any dirt, oil or paint which may be present.
  • Standard length of conduits shall be cut to the required length.
  • For GI Conduits threading shall be done using a threading tools and appropriate die-set. Thread will be kept to a minimum from coupling and boxes. Zink rich paint to be applied to the exposed thread part of GI conduit.
  • Where required conduits shall be bent to the required radius using manual bending machines.
  • Conduits are fixed to the building fabric by means of distance saddle with appropriate metal screws will be allowed.
  • Spacer bar are fixed in regular interval not exceeding 1000mm and the distance from either side of ay box or bend to the nearest spacer bar shall not be more than 150mm.
  • All terminal boxes area marked on the appropriate location (wall/ceiling) as per approved shop drawing and fixed with metal screws and plug. Suitable bushes are used where conduit enters the boxes to avoid any damage to the wires.
  • Wherever necessary ropes shall be pulled into conduit runs ending and kept at pull boxes for the future purpose. Ensure that sufficient number of pull boxes is installed.
  • Metallic conduit boxes shall be sued throughout metallic conduit raceway system.
  • GI flexible conduits shall be used to make connections from un-accessible location and end connections to terminal boxes.
  • All pull boxes, junction boxes fixed on the wall in the route of steel conduit shall be provided with GI cover after pulling the wires.
  • Steel conduiting shall be conforming to relevant IS specifications (IS 9537). All steel conduits shall be of heavy gauge, welded and threaded type.  Conduit accessories such as boxes, bends, inspection bends, boxes, elbows, reducers, etc. shall conform to relevant standards.  As far as possible, boxes shall have internally tapped spouts to receive the conduits.
  • Where conduits are installed in straight run, draw boxes shall be provided at intervals not exceeding 30 feet (9 meters). Between two consecutive draw boxes, the right angle bends shall not exceed two in number. Conduits shall be properly threaded and screwed in to the accessories.
  • The minimum size of conduits used shall be 20 mm. The minimum thickness of the conduits shall be 16 SWG.
  • Wherever steel conduits terminate into points control boxes, distribution boards, etc. conduits shall be rigidly connected to the boxes, boards, etc. with check nuts on either side of the entry to ensure electrical continuity and with PVC or Bakelite bushes. Turning joints in conduits wherever necessary shall be rigidly held in aligned position by check nut tightened on the running side.
  • After conduits, junction boxes, outlets, etc. are fixed in position, their outlets shall be properly plugged with PVC stop cover or with any other suitable material so that water, mortar, vermin or any other foreign material do not enter into the conduit system.
Maximum number of PVC insulated 650/1100 V Copper conductor cable conforming to IS: 694-1990
Conduit size 20mm 25mm 32mm 40mm 50mm
Wire Size (Sq.mm) S B S B S B S B S B
1.5 Sq.mm 7 5 12 10 20 14
2.5 Sq.mm 6 5 10 8 18 12
4 Sq.mm 4 3 7 6 12 10
5 Sq.mm 3 2 6 5 10 8
10 Sq.mm 2 4 3 6 5 8 6
16 Sq.mm 2 4 3 7 6
25 Sq.mm 3 2 5 4 8 6
The columns heads ‘S’ apply to runs of conduits which have distance not exceeding 4.25 m between draw in boxes and which do not deflect from the straight by an angle of more than 15 degrees.
 The columns heads ‘B’ apply to runs of conduit which deflect from the straight by an angle of more than 15 degrees.

Bending of Conduit:

  • It may be necessary to create bends in the field by heating and deforming rigid conduit.
  • For heating the rigid conduit, use a heat gun or some other flameless heat source. Do not use an open flame to heat the conduit. The rigid conduit must be heated to approximately 125˚C in order to bend without kinking.
  • Heat a length of conduit equal to approximately 10 times the rigid conduit nominal diameter.
  • Once the rigid conduit has been adequately heated, bend it to the required angle plus 3 extra degrees. The additional angle will accommodate the “spring back” which will occur during cooling.
  • After bending of the conduit is completed, immediately cool the bend using water or cold air.
Conduit Bending Radius
Size of Conduit Radius to Center of  Conduit
12  mm 100 mm
20 mm 112 mm
25 mm 144.8 mm
30 mm 183.9 mm
40mm 208 mm
50 mm 238 mm
63 mm 266 mm
75 mm 330 mm
88 mm 370 mm
100 mm 403 mm
127 mm 609 mm
152 mm 762 mm

REFERENCES:.

  • IS 3854 1966: Switches for domestic and similar purpose.
  • IS 1293 1967: Three pin plug and socket outlets.
  • IS 4614 1968: Switch Socket outlet (non-interlocking type)
  • IS 6538 1971: Three pin plugs made of resistant materials.
  • IS 9537-3 (1983): Rigid plain conduits of insulating materials.
  • IS 3419 (1989): Fittings rigid non-metallic  conduits

Method for Installation of Conceal & Surface Conduits (Part-1)


(A) Purpose: .

  • This method explains the sequence of activity for safely installation of PVC / GI Conduits and it’s accessories in the concrete slabs / columns, in block works and on Surface as per the standard Practice and Code.

(B) 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.
  • If the Material is found defective it shall not be installed and the cable shall be returned to the supplier for replacement.

(C) Inspection of Materials:.

  • Check The Material according to its Type, Size, Make
  • Visual inspection:
  • Type and Make of Conduit and Accessories Material
  • Length , Width and thickness of PVC / GI / MS Conduit Material and Accessories
  • Physical Damages Inspection:
  • Damage on Material and it’s Accessories
  • In case of any damages observed during inspection, the concern report will be issued and Material shall be returned to the supplier for replacement.

(D) Concealed Conduit in Slab / Column:.

  1. Shifting Material to Working Area:

  • PVC Conduit and its accessories 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 material is free from transportation damages
  • Check and ensure that approved drawings, the correct size and type of Conduit & its accessories are ready for installation.
  • Ensure that Conduit and its accessories received from site store for the installation are free of rusty parts and damages.
  1. Marking Electrical Point / Wall Conduit Drop on Slab:

  • Ensure that the civil activities are finished I,e Slab Shuttering Work and Steel Work and Site is ready for Electrical Work on Slab.
  • After completing the first layer of steel, start marking of Ceiling Points and Wall Drop Points on Slab as per approved Site Drawings.
  • Mark first the wall location for lower floor in slab as per latest Architecture layout so that it will be easy to locate the drops for switch, Wall Light Points and any other drops required for electrical system.
  • Mark the opening size in Slab or in Beam i.e window, door and shaft as per approved electrical drawing to avoid passing wall conduit drop on that area.
  • Mark the Electrical points on the slab, Wall Conduit Drop in Beam as per approved Electrical Shop Drawing.
  • Make sure that marking of Wall conduit drop is placed in center of wall, it is not out from wall or not move to any face of wall.
  • For initially use marker / Chalk for making location of electrical point on slab and wall drop after that apply oil paint on that location before conducting work so after de shuttering ,the JB or conduit drop is easily visible on slab or on beam.
  1. Installation of Junction Box and Conduit:

  • Chalk will be used to mark the PVC conduit route. Make sure that size of conduit is as per approved Electrical Shop Drawing.
  • Ceiling Conduits shall be laid on the prepared shuttering work of the ceiling slab before concrete is poured. The conduits, boxes, accessories, joints, etc. shall be laid along with the conduits.
  • Use Deep Junction Box for surface mounted lighting Fixtures and for Cable Pulling.
  • Use long radius bend or make as per site requirement by using PVC Conduit bending spring.
  • Joints between PVC conduit + fittings shall be made with suitable adhesive.
  • Try to avoid the overlapping of conduits and keep some distance between the conduits for low current and power/Lights.
  • To maintain at least 20mm spacing gap between PVC conduits running in parallel. To allow adequate / sufficient space between formwork and conduit so that embedded conduit is fully covered by concrete and will not result in any honeycomb or structural defects in the future.
  • Concealed conduits in slabs shall be brought out as vertical drops in beams, wherever such drops are required.  All vertical conduits in beams shall be left protecting from the bottom of the beam. All such ends of conduits protecting from bottom of beams shall be provided with couplings to receive extension.
  1. Fixing of Conduit & Accessories:

  • The conduits shall be adequately fixed to prevent excessive movement and damage during the pouring and setting of concrete and shall be protected from mechanical damage.
  • For Double layer of rebar, PVC conduits shall be secured to the bottom of Top layer rebar and for Single Layer rebar, PVC Conduit should be secure at top of rebar with binding Steel Wire.
  • After completing the work, tight the conduits with binding wire .PVC Conduit should be bound at intervals of not more than 1 meters by binding short lengths of steel wire, of not less than 2mm diameter twisted around the conduit and reinforcing steel. Additional Steel bonding Wire also provide near each PVC Conduit Coupler, PVC Bends and near Junction Box
  • Check there is no damage in PVC Conduit and it’s accessories before concrete is poured.
  • The open ends of Conduit should be protected during concreting by caps or plugs to prevent the ingress of building material.
  • All Junction Box, Fan Box should be protected during concreting by filling thermo coal Sheets to prevent the ingress of building material.
  • Ensure conduits are not concealed until works has been inspected and approved.
  • Before the concrete pouring the PVC conduit installation to be inspected and approved by consultant/client/contractor.
  • During concrete pouring, keep electricians for taking care of conduit to avoid any damage by others or dislocation of joints.

(E) Recess / Concealed Conducting in Wall.

  • Ensure that bricks / Block masonry work is complete and Site is given for electrical works.
  • Check the required reference markings are available for FFL (finished floor levels).
  • All required materials shall be shifted and stored under safe custody near workplace on daily basis as per planned quantity.
  • In the case of building under construction, conduit shall be buried in the wall before plastering and shall be finished neatly after erection of conduit.
  • In case of exposed brick/rubble masonry work, special care shall be taken to fix the conduit and accessories in position along with the building work.
  1. Marking of Switch Box and Light Points:

  • Mark the location of switch/socket and conduit route on proper height based on approved shop drawing.
  • No conduit smaller than 20mm in diameter or larger than 32mm diameter shall be used.
  • Mark the location of Switch Box, DB, and Junction Box for Light Point on the wall from FFL.
  1. Wall Chasing:

  • After marking of conduit and Switch Box location, Wall chasing shall be done using wall cutting machine.
  • Hammer and chisel will be used on the chased portion to get uniform depth of 50 mm or as per standard specifications.
  • All chases, grooves shall be neatly made to proper dimensions to accommodate the required number and size of conduits and staples. The outlet boxes, point control boxes, inspection and draw boxes shall be fixed as an when conduit is being laid. The recessing of conduits in walls shall be so arranged as to allow at least 12 mm plaster over the same. 
  • The chase in the wall shall be neatly made and of ample dimensions to permit the conduit to be fixed in the manner desired.
  • Wherever the length of conduit run is more than 10 meters, then circular junction box shall be provided to permit periodical inspection and of facilitate replacement of wires, if necessary. These shall be mounted flush with the wall.
  • In place where the conduit is crossing at different ceiling height, uniform bending shall be done. The bending of conduit shall be done using proper bending springs.
  • Conduits will be cleaned with a round file from inside and outside of the pipe after cutting.
  • Connect the conduit by using PVC solvent with an adaptor to the junction box. Apply PVC Solvent cement on the portion of conduit entering into coupler wherever applicable.
  • PVC Conduits shall be duly fixed by using a hook or Nail. Distance of GI hook / Nail shall be maintained at 500 mm at intervals.
  • Embedded back box, JB shall be protected by covering with brown tape filled with jute/gunny bag.
  1. Installation of the Box / Enclosure:

  • At Planning and Designing Level, always Select DB Wall block work thickness should be 200 mm instead of 100 mm for easy DB installation.
  • For Properly Installation of DB and Switch Box, locate plaster level points near DB or Switch Board.
  • The mounted height of the Switch Board is generally 1200mm (Bottom of Switch Box) in all rooms ,300 mm near Bed and for DB it is generally 1800mm (bottom of panel) or as per approved Drawings.
  • Ensure the box size and accordingly cut a bit larger size of box in marked place of block wall with sufficient depth.
  • Fix the GI Metal box of appropriate size and level with the help of spirit level.
  • Installed the Switch Box and DB with the use of cement mortar around the box. Make sure that it is flush with finished plaster level.

s

  • The bottom portion of box should match the marked level as per consultant approved height for switch/ socket and/or as per local applicable wiring regulation requirements.
  • Apply cement filler to fix the box properly and leave for setting, insert the required lengths of conduits on their paths and don’t connect with boxes until next day.
  • Next day, after setting of box connect the dropped conduits for switch/socket to the box.
  • The switch box shall be flush with the plaster. The height of the switch boxes shall be as indicated in the drawings. The switch boxes should be sufficient depth to give minimum 20 mm plaster cover to conduits embedded.
  • Distribution board interiors will not be installed in cabinets until all conduits connections to the cabinet have been completed.
  • Trim for flush mounted cabinets will be installed in plaster frame, flushed with furnished wall.

Quick Reference-Fire Fighting (Part-3)


 

Pipe Support Details

Nominal Pipes Diameter

Hanger rod diameter

Hanging Strip Size(thickxwidh)

Spacing between supports

25 mm

8 mm

20 x 1 mm

2 Meter

32 mm

8 mm

20 x 1 mm

2.5 Meter

40 mm

8 mm

20 x 1 mm

2.5 Meter

50 mm

10 mm

25 x 1.2 mm

2.5 Meter

65 mm

10 mm

25 x 1.2 mm

2.5 Meter

80 mm

10 mm

25 x 1.2 mm

2.5 Meter

100 mm*

12 mm

25 x 1.6 mm

2.5 Meter

125 mm*

12 mm

25 x 2 mm

3 Meter

150 mm*

12 mm

25 x 2 mm

3 Meter

* As per Site Requirement Fabrication Support may be used.

Sprinkler Qty

Pipe Size

Min.Sprinkler Qty

Max.Sprinkler Qty

25 mm

1

2

32 mm

3

4

40 mm

5

7

50 mm

8

15

65 mm

16

30

80 mm

31

60

100 mm*

61

100

150 mm*

More than 100

Supporting Chanel & U Bolt

Pipe Size

Chanel

U Bolt Dia

Up to 50 mm

38x38xx6 mm

9 mm

65 To 100 mm

75x75x6 mm

12 mm

125 To 200 mm

88x88x9 mm

15 mm

 

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

Pipe Support Details

MS Angle(mm)

Anchor Faster

Width

40X40X5

12MM

200MM both Side of Pipe

Holiday Test Voltage (IS 15337)

Thickness of Coating

Test Voltage, Max

2 mm

10KV

3 mm

12KV

4 mm

15KV

Recommended Welding Electrode Size

Average Thickness of Plate or Sections

Maximum Electrode Size

Current Range

1.5 To 2.0 mm

2.5 mm

60 To 95 Amp

2.0 To 5.0 mm

3.2 mm

110 To 130 Amp

5.0 To 8.0 mm

4.0 mm

140 To 165 Amp

>8.0 mm

5.0 mm

170 To 260 Amp

Method for Wrapping Coating & Holiday Test for Fire Fighting Pipe


Purpose:

  • This method describes the detailed procedure for installation & Testing of Wrapping Coating and Holiday Test for Fire Pipes as per the standard Practice and Codes.

General Equipment & Tools:

  • The equipment that will be engaged for Installation of Fire Pipe works will be
  • Tool Box
  • Welding Machine
  • Grinding Machine
  • Cutting Machine
  • Chain Block
  • Pipe Wrench
  • Hand Tools-gloves.
  • Hammer
  • Portable Lights
  • Manual Excavation Tools
  • Removable Barricades
  • Scaffolding / Mobile scaffold
  • Ladder
  • Spirit Level
  • Marker
  • Holiday Test Machine
  • Measuring tape

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 transported in their original packing to Site location.
  • All materials shall be stored in a covered warehouse in a location as cool as possible and protected from the ingress of dirt, dust, moisture, etc.
  • Any coating materials show evidence of deterioration due to weathering or damage due to mishandling while are in the custody contractor, shall be replaced by the contractor.
  • Chemicals must be stored in well ventilated location and away from direct sunlight.

Inspection of Materials

  • Inspection of Wrapping Coating:
  • Check the reference of delivered material against approved submittal.
  • Check the material against the purchase order.
  • 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 Material shall be returned to the supplier for replacement.

Sequences of Wrapping Works:

  • wrapping system shall comprise the followings sequences:

(A) Surface Preparations:

  • Prior to brush cleaning, all oil, grease on the pipe surface shall be thoroughly removed by flushing with suitable solvent and wiping with clean tags.
  • Rusted materials surface shall be adequate scrubbed manually with stiff wire brush where ever surface get rusted, prior to application of primer.
  • Surface shall be completely free from rust, mill scale, grease, weld spatter, weld slag, dirt, dust, oil and any other foreign matter and to be dry at time of application.
  • Oil and grease shall be removed using an approved solvent. White spirit and paint thinners are suitable solvents. Kerosene shall not be used.
  • Mechanical cleaning machines shall not employ knives or other tools, which may produce notches or gauges on the pipe surface.
  • Blast cleaning machines shall be maintained in correct adjustment and replacement tools shall be available throughout the cleaning process.
  • All weld joints shall be cleaned manually with stiff wire brush/buffing
  • The coat of primer shall be given as soon as practicable and before detrimental corrosion or recontamination occurs. The cleaned surface shall never be left unprotected overnight.
  • The cleaning method employed shall not result in thinning of the pipe wall beyond the limits of the pipe specification.
  • Cleaning shall be carried out immediately before application of the priming coat and shall be to the satisfaction of OWNER. If the outside of the pipe becomes contaminated with any foreign matter.

(B) Application of Primer:

  • Immediately after cleaning the surface shall be applied with one coat of primer before application of coal tar wrapping. The entire surface of pipe should be primed.
  • The primer shall be applied in a thin layer without runs, sags, drips, holidays (gaps or voids) or other defects.
  • If any defects may be found in the primed surface, the pipe shall be re-cleaned and primed to the required standard and to the satisfaction of principal/engineer.
  • No specific time gap between two coats needs to be maintained but after the coat of primer, the coating should before the primer is completely hardened.
  • The primer shall be suitable for brush or spray application and still form at thin uniform coating with an approximate 40 micrometer dry film thickness according to vendor’s instruction.
  • Freshly primed pipe shall be properly supported on racks, and allowed to be uncontaminated by moisture, dirt or other foreign matter.
  • 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.
  • Coating and wrapping shall not be started until that section of line has been tested and accepted.
  • The primer shall be suitable for brush or spray application and still form at thin uniform coating with an approximate 40 micrometer dry film thickness according to vendor’s instruction.
  • Primer shall be applied at an average rate 0.12 liter per square meter.

(C) Application of Coating (Wrapping):

  • The pipe shall be kept on a suitable platform with ease of rolling so that the enamel can be applied manually with brush/spray so that it will spread uniformly on the metal surface.
  • Immediately, wrap of coal tar as per approved specification shall be applied over the coal tar enamel.
  • The total, clean, dry prepared surface shall be spirally wrapped with the laminated tape with min 15 MM or as per Specification overlapped using sufficient tension to ensure complete conformability. Any bulges formed at covers may be removed by splicing the tape in site and repress ring.
  • The inside of the coal tar is heated with burner and is pressed against the metal with hands so that there is no air gap and with required overlap (i.e. 15mm).The coating shall be continuous for the full length of the pipe except 200 mm at both ends of the pipes.
  • The tape shall be applied with tension controlled provide a uniform, tightly adhesive coating free from wrinkles, puckers, void, or break.
  • When the wrapping shall be performed “AT SHOP” or “AT SITE” (when it is necessary to stock the wrapped pipes), an outer wrap shall be spirally wound over a clean dry Primer with 15 mm minimum overlap using sufficient tension to ensure complete conformity. No bulges shall be permitted.
  • End laps between adjoining rolls of the wrap or between pipe sections shall be a minimum of 150 cm
  • There after the pipes are lifted by suitable methods and allowed to dry on wooden sleeper/Sand bags. It is done at 2meter distance from digging area.

(D) Handling of Coated Pipe:

  • All coated pipes shall be handled in such a way that the coating does not suffer damage.
  • Coated pipe shall be handled at all times with wide non-abrading slings or belts, or other equipment designed to prevent damage to the coating. All skids used to support coated pipe shall be padded.
  • Bar cables, chains, hooks etc. shall not permitted to come in contact with coatings. Coated pipes shall be supported at two bare ends cleared from ground either on kids or sand bags.
  • If the pipeline protective coating suffers damage between the coating and laying operations, the Contractor shall replace or repair the coating to the satisfaction of the OWNER
  • Pipe shall normally be lowered into the trench immediately after the coating and wrapping has been approved. Where coated and wrapped pipe is supported on padded skids, their number shall be sufficient to ensure that no damage will be caused to the coating and wrapping.
  • All coated and wrapped pipes which have been supported in any manner on padded skids, or lowering devices, shall be subjected to closed inspection to see that the coating is undamaged before the pipe reaches the bottom of the trench.
  • Backfilling shall be carried out immediately after the pipeline is lowered into the trench but Contractor shall first obtain the approval by OWNER. If any backfilling is carried out without this approval, OWNER will have the right to require the Contractor to remove the backfill for examination of the coating and wrapping.

(E) Inspection of Wrapping Pipe:

  • After application of tape coating, visual inspection shall be carried out for uniformity without any wrinkle, irregularities and over lapping width.
  • Visual inspection shall ensure that the coating is continuous, that the overlap is correctly maintained and that there are no wrinkles in the tape.
  • All coating shall be subjected to 100% visual inspection and 100% inspection with an electrical holiday detector before being lowered into the trench.
  • Thickness of the coal tar enamel coating shall be measured with the digital thickness gauge. Minimal acceptable thickness shall be 4mm or as per Specifications.

Testing of Wrapping by Holiday Test:

  • The holiday detector shall be used to check that there is a continuous coating over the pipe surface, particular attention being given to bends and to areas where the tape has been spliced or repaired.
  • Holiday detection shall be carried out only in dry weather conditions.
  • Inspection for holidays are carried out on all buried field and shop components prior to backfilling. All field joint coated areas to be tested & free from contaminants such as sand, grease and moisture. It shall be performed on completely finished coatings.
  • Prior to back filling, all wrapped pipe shall be holiday tested using an approved holiday tester set at 5KV per mm of tape thickness to a maximum of 15KV.
  • The holiday detector shall be of an approved type and the operating voltage and setting shall be determined by a method approved by OWNER.
  • The holiday detector settings shall be checked at least twice per day, while it is in use.
  • The calibration report for the Holiday detector will be submitted for review before carrying out Holiday detector testing.
  • Testing Voltage:
  • The applied output voltage of the holiday detector shall have a spark discharge of thickness equal to at least twice the thickness of the coating to assure adequate inspection voltage and compensate for any variation in coating thickness. The electrode shall be passed over the coated surface at approximately half the spark discharge distance from the coated surface only one time at the rate of approximately 10 to 20 nd min.
  • The edge effects shall be ignored. Excessive voltage shall be avoided as it tends to induce holidays in the coated surface thereby giving erroneous readings.

Test Voltage (IS 15337)

Thickness of Coating Test Voltage, Max
2 mm 10KV
3 mm 12KV
4 mm 15KV

  • The electrical equipment used to test tape wrapping shall be a portable, low amperage, adjustable voltage, pulse type holiday detector. It shall be furnished with a coil spring electrode or, a suitable brush type electrode. The primary input wattage shall not be higher than 20 W and the minimum pulse at crest voltage shall be 20 per second.
  • The wrapping machine shall be equipped with an overlap control device properly adjusted to provide the following minimum overlap under all conditions
  • Testing Method:
  • The Visual inspection of the wrapped and coated is carried out to see that the overlap is correctly maintained and there are no wrinkles, voids, blisters, pinholes, open seams, entrapped air or any other defects likely to cause failure of the coating.
  • The electrode of the holiday detector, which is in the form of a coil spring, is put on the surface of the coated pipe.
  • The voltage of the holiday detector is set by the operator using the adjustable knob.
  • At no point of time the voltage will be allowed to go beyond 15000V. To ensure proper inspection voltage the equipment shall be grounded properly and the voltage adjusted in accordance with the instructions of the equipment manufacturer.
  • After the voltage adjustment the electrode shall be passed over the taped surface one time only at the rate of approximate 15 m /min. If the electrode shall be passed over the coated surface, the current to the electrode should be immediately cut off to avoid damaging the coating.
  • The location of the holiday should be marked using chalk/crayon. That 3” on either side of defective portion of the tape is to be cut opened and removed and fresh tape of that size or slightly larger than that is to be applied using the same application procedure.
  • The repaired area shall then be retested once again with the holiday detector.
  • The report for the above test will be documented as per approved format.
  • Precaution:
  • It is not intended that the holiday detector should be used to reveal pin holes and minor faults in the inner tape wrap. Such defects would not normally show up on the holiday detector with the specified coating system, unless the voltage was set at a level, so high, that it would be likely to damage the coating.
  • At no time, shall the holiday detector be permitted to remain stationary around a coated pipeline with the operating voltage switched on.
  • All defects, whether discovered visually or by means of the holiday detector, shall be clearly and indelibly marked.
  • To ensure continuity between the brushes or rings, a short circuit test shall be carried out at regular intervals to determine the efficiency. If brushes are used, these must be cleaned every day.

 Repair of Wrapping Coating:

  •  All defects in the coating shall be made good immediately after their detection.
  • In the time of holiday test if any defective work is found, remove the wrapping and coating to the required extend from those areas by using a sharp knife. Then heated enamel shall be applied manually over the area following the procedure described above and inner and outer wrap applied.
  • The Contractor shall be responsible for the complete cost, including cost of materials, of making good all defects caused by incorrect storage, handling, application, erection and testing of the protective coating or caused by incorrect construction of the pipeline.
  • In the event of numerous defects in the coating, OWNER shall have the right to order the whole coating to be stripped, the pipe cleaned and another coating provided, applied and tested in accordance with this specification at the Contractor’s expense.
  • Holiday or localized defects in the inner tape wrap shall be repaired by the following procedure:
  • (a) Strip off outer wrap from affected area, after ensuring that completed coating on either side is properly secured to prevent the outer wrap from unraveling.
  • (b) Strip off inner wrap and primer from the affected area and thoroughly clean the pipe surface.
  • (c) Re prime in accordance with this specification.
  • (d) Apply patch of inner wrap not smaller than 150 mm x 150 mm (6″ x 6″).
  • (e) Test for continuity of repaired inner wrap with holiday detector before replacing outer wrap.
  • (f) Replace outer wrap and secure firmly.

References:

  • Project Specification.
  • IS 10221
  • IS 15337
  • NFPA (National Fire Protection Association) Code.
  • NBC Code.

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.

Painting:

  • 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./sq.cm. 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

References:

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

122

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


Purpose:

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/Sq.cm. 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)


(4) ELECTRICAL CHECKS BEFORE CHARGING THE  PANEL

  • TESTING CONTINUITY BETWEEN ALL METAL PARTS AND GROUND
  • For performing this test, it is generally recommended to use a milliohm meter for continuity measurement.
  • INSULATION RESISTANCE TESTS For SWITCHGEAR
  • 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. 

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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.

FLOW CHART:

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


Purpose:  

  • 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.

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(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.

2

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

3

  • Install the panel in proper alignment and fix properly.

4

  • 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)

Galvanizing

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.

 

OVERLAPING OF EARTHING STRIP

Size of Earthing Strip

Minimum Over Laping

20×3

20MM

20×6

20MM

25×3

25MM

25×6

25MM

32×6

25MM

40×5

50MM

40×6

50MM

50×6

50MM

50×10

50MM

75×6

50MM

75×10

50MM

 

NO’S AND SIZE OF NUT BOLT FOR JOINTING EARTHING STRIP

Size of Earthing Strip

Minimum Nut Bolt Required

Minimum Size of Nut Bolt

20×3

2 NO’S

8X25MM

20×6

2 NO’S

8X25MM

25×3

2 NO’S

8X25MM

25×6

2 NO’S

8X25MM

32×6

2 NO’S

8X25MM

40×5

4 NO’S

8X25MM

40×6

4 NO’S

8X25MM

50×6

4 NO’S

10X25MM

50×10

4 NO’S

10X25MM

75×6

4 NO’S

10X25MM

75×10

4 NO’S

10X25MM

 

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

Gauge Gms.

mm

Weight Kg / Meter.

4

5.892

0.216

6

4.876

0.148

8

4.064

0.103

10

3.251

0.066

12

2.641

0.045

14

2.032

0.026

16

1.625

0.017

 

Weight of G.I Flat Strip

Sizes in (HxW)

Kgs/Per meter

Application

20×3 mm

0.49

Lighting Arrestor

20×6 mm

0.98

PLC Panel

25×3 mm

0.6

 

25×5 mm

0.97

 

25×6 mm

1.3

Control & Relay Panel

32×5 mm

1.21

Lighting Panel & Local Panel

32×6 mm

1.625

Distribution Board

40×3 mm

0.964

Motors 5.5kw-55Kw

40×5 mm

1.476

 

40×6 mm

1.92

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

50×3 mm

1.28

50×5 mm

1.92

50×6 mm

2.56

50×10 mm

4

Transformers Substations

62×6 mm

3.07

65×10 mm

5.2

75×10 mm

6

75×12 mm

7.2

 

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.

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  • 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.

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  • 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

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