Internal Electrification
Standard drawings invariably show the exact locations of these points and fittings and no deviations will be made.During construction it should be ensured that these positions are not changed through oversight or negligence.Dunng execution the following points which are common to all types of wiring should be carefully watched :
a) Ensure that neutral and live wires are correctly marked at point of supply.
b) Position of lights, fans, switches etc should be as per drawings and should be marked on the walls and approved before execution.
c) Schematic diagram and circuit should be made before starting the work and adhered to.
d) Power circuits should be separate from the lighting circuits.Finishing Items Etc.Work Supervision Check List
e) All channels in walls for conduit wiring should be provided during construction as far as possible. No plastering will be permitted till after conduits and boxes are laid. Similarly all conduit in RCC roofs, RCC beams and floors etc must be laid before concreting.
f ) All wiring should be done by looping system.
g) Ensure that aluminium conductor is connected to switches, plugs, ceiling roses etc with the recommended jelly to ensure permanent contacts.
h) While drawing aluminium conductor cables through conduit, ensure that these do not break at any point. Check continuity periodically.
i) Ensure that there are no kinks in the wires.
j)Ensure that all crossings through the wall are done either with porcelain tube or conduit where wcn~den bushes should be provided at the ends.
k) The specifications for internal wiring as laid down in SSR for NIES should be strjctly followed.
l) Main switch should be easily accessible.
m) Ensure that pole for service connection is so fitted that rain water does not get into the pole.
Following points should be watched during the execution of different types of wiring:
A) TRS Wiring on Teak Wood Battens
a)Use planes, seasoned, dried and varnished teak wmd. The size will depend on the number of wires to be carried on it.
b) It should be fixed on wall by brass screws and raw1 plugs or wooden gutties. The wire should be laid with brass clips and brass nails.
c) The distance between screws should be (9") 23 cm and nails (6") 15 cms.
d) Ensure that wooden blocks, boards etc are of seasoned dried teak wcmd and are varnished and are fitted flush with the wall surface.
e) TRS (tough rubber sheathed) cable should be as IS1 specitlcation No 434 of 1965.
Standard drawings invariably show the exact locations of these points and fittings and no deviations will be made.During construction it should be ensured that these positions are not changed through oversight or negligence.Dunng execution the following points which are common to all types of wiring should be carefully watched :
a) Ensure that neutral and live wires are correctly marked at point of supply.
b) Position of lights, fans, switches etc should be as per drawings and should be marked on the walls and approved before execution.
c) Schematic diagram and circuit should be made before starting the work and adhered to.
d) Power circuits should be separate from the lighting circuits.Finishing Items Etc.Work Supervision Check List
e) All channels in walls for conduit wiring should be provided during construction as far as possible. No plastering will be permitted till after conduits and boxes are laid. Similarly all conduit in RCC roofs, RCC beams and floors etc must be laid before concreting.
f ) All wiring should be done by looping system.
g) Ensure that aluminium conductor is connected to switches, plugs, ceiling roses etc with the recommended jelly to ensure permanent contacts.
h) While drawing aluminium conductor cables through conduit, ensure that these do not break at any point. Check continuity periodically.
i) Ensure that there are no kinks in the wires.
j)Ensure that all crossings through the wall are done either with porcelain tube or conduit where wcn~den bushes should be provided at the ends.
k) The specifications for internal wiring as laid down in SSR for NIES should be strjctly followed.
l) Main switch should be easily accessible.
m) Ensure that pole for service connection is so fitted that rain water does not get into the pole.
Following points should be watched during the execution of different types of wiring:
A) TRS Wiring on Teak Wood Battens
a)Use planes, seasoned, dried and varnished teak wmd. The size will depend on the number of wires to be carried on it.
b) It should be fixed on wall by brass screws and raw1 plugs or wooden gutties. The wire should be laid with brass clips and brass nails.
c) The distance between screws should be (9") 23 cm and nails (6") 15 cms.
d) Ensure that wooden blocks, boards etc are of seasoned dried teak wcmd and are varnished and are fitted flush with the wall surface.
e) TRS (tough rubber sheathed) cable should be as IS1 specitlcation No 434 of 1965.
B) Concealed Conduit Wiring
a) Ensure that correct size of the conduit is used depending upon the s i ~ e and number of wires.
b) Ensure that all conduits are electrically connected to earth either by bonding at all joi* or by running a continuous earth wire of copper or GI.
c) Ensure that conduit ends have no sharp burrs as they damage the wires when pulled .through with a steel wire.
d) The boxes for switches, sockets etc should be fitted flush with the wall.
e) Ensure that conduit is fixed in the wall chasses with clamps and the chasses then filled with cement mortar before plastering the wall.
f)The wires through the conduits should be pulled straight and with uniform pull. It should. be done with steel flexible wire commc)nly
known as 'fish wire'.
g) After laying the conduit at the installation the conduit ends should be sealed against likely entry of water and cement slurry while plastering the wall.
C) Surface Conduit Wiring
a) Ensure that conduits are fitted properly in clamps and are not subjected to any load.
b) Earthing should be continuous and properly jointed at the joints.
c) All conduit boxes should be securely screwed and fitted with :heck nuts.
d) Ensure that conduits are laid straight and do not present unsightly appearance.
e) Surface conduits will be laid where authorised and will not be laid on plastered walls.
Earthing
a) Ensure that either an earthed terminal is provided by the supplier at the point of supply or the building has its own efficient earth so that all earth connections are connected to it.
b) Ensure that all non-current carrying metal parts of electrical fittings are connected with continuous earth wire to an independent earth except for those given in IE Rules Para 61 sub para 3 such as isolated wall bracket, switches etc.Earthing with gas pipes or water pipes is not allowed.
HVAC Works
Layout and Site Examination
a) On the layout plan of the building, mark out the locations and sizes of the impartant rooms and facilities so that there are no changes during execution.
These should include:
i)Plant room
ii) Weather making room
iii) Air handling units
iv) Cooling towers and water softening plant if provided. Where possible, these should be on top of the plant room.
v) Electric substation
vi) Water mains
vii) Drainagdsewers
viii) Stand by power house, if any
ix) Contractor's fabrication area
b) Check the sizes of the various plant rooms to ensure that these are adequate to house the plant and leave enough space for maintenance.
c) Check that available services like water, electricity, sewage are adequate. If not initiate action for their mcxiification.
d) Check that there will be no hold up during execution due to unforeseen site conditions.
Airconditioning Layout of Operation Theatre
a) In an operation theatre, recirculation of air is not permitted. Verify and ensure that proposed layout caters for this.
b) To ensure that contaminated air does not infiltrate into sterilized zone, check that layout provides for flow of air from operation theatre outwards to non-sterilized zone.
Coordination With Civil Engineering Works
a) Indicate on a plan the location and sizes of ducts diffusers and return gills.This should be given to the design section for incorporation in the plans.
b) Finalize the arrangements for fixing ducts so that necessary hwks etc can be left in the roof slabs where necessary.
c) Ensure that a time table is made out for handing over the various rooms to the a&conditioning contractor for installation of the equipment. Watch that this is adhered to.
iCPM Chart
Prepare CPM Chart for the airconditioning works and get it correlated with the CPM Chart of the building works. Review the chart periodically. Ensure that all activities are commenced and completed as planned.
Construction and Installation of Ducts
a) Sketch out the supply and return duct system
b) Indicate various sizes of duct sections, as per design
c) Fix location of outlet diffusers and return grills.
d) Check material for duct construction for quality and thickness
e) Ensure joints are made in accordance with IS: 655-1963 and reinforcement provided for rigidity.Inspect all branches, elbows etc before assembling.
g) After assembling, check seams and corners for air tightness. During construction, ensure that there are no sharp internal edges as these will generate noise.
h) Ensure that hanging arrangements are rigid and there is no strain on the joints.
i) Ensure dampers are installed in correct locations
j)Remember that fan, ducts, dampers, .diffusers return grill and return ducts form one correlated system. Change in any of these is likely to upset air balancing of the system.
k) When c~ossing walls, ensure that ducts are properly packed with felt/fiberglass to reduce noise and to prevent leakage from the room.
l) Ducts which are outside the conditioned space should be adequately insulated.Use vapour barrier to prevent moisture condensation inside the insulation materi d .
m) Bovide flexible canvas joints to prevent long duct system from vibrating like a string.
n) After final installation, check for vibration and noise at N1 design flow of air.
o) Large ducts should be provided with access doors for cleaning.
Installation of Chilled Water Mains
a) Ensure thorough internal cleaning of the pipes.Any lapse in this will cause serious damage to the system, as dirt will clog up the orifices, .
b) Check that suspension arrangements are as per design.
c) While fixing insulation, ensure that there is no moisture on the pipe.
d) After completing the installation, the following procedure should be gone through:
i)Bypass all controls and equipment with small tubes/c)rifices,
ii) Flush the pipeline with clear water till it appears to be clean.
iii) Load the system with 1 l b of trisodium phosphate to every 50 l b of water and circulate this by means of a pump for 8 hours.
iv) Then drain and flush with clean water.
v) Check with litmus papei the pH value; it should be 7.5. If high repeat the cleaning process and flush.
Check Lid
Location of Fresh Air Inlet
a) While locating the outside air inlet, ensure that surface dirt will not be drawn into the system.
b) Inlets taken above roof should be high enough to clear parapet walls.
c) Ensure that inlet is not in line with neighbourhood chimneys.
d) Inlet shciuld not be exposed to prevailing winter wind.
e) Ensure that proper louvers are provided at the inlet to keep out rain, birds and other objects.
Diffusion Devices
a) Check that conditioned air is not directly deflected towards an air return.
b) See that air flow does not strike walls, beams, or other obstructions.
c) See that no obstruction is placed in the air return passage.
d) Check that the adjustment of grill frets does not result in the supply air striking directly the thermostat.
e) Lowside wall or flush floor diffusers should be so adjusted that air is deflected properly upward for cooling and downward for heating.
Heading Furnaces
a) Check that adequate height of chimney is provided. The end of chimney should ,be protected by a hood.
b) Check that all the controls are tested before being installed.
c) Oil burners are meant to be used with a specified oil. Check the specification of the burner being provided. Inspect the test certificate which should normally be with the burner.
d) Ensure that adequate fuel storage is provided.e) See that unit incorporates safety control for temperature, ignition failure and over heating.
Heating Boilers
a) Check the manufacturer's data and verify that the boilers are according to the laid down specifications.
b) Ask for manufacturer's test certificate for the boiler working pressure. Boiler should be inspected by own bdler Inspector after the installation is completed and before it is commenced.
c) Check that Chimney height is adequate to produce the draft as laid down by
the makers.
d) Ensure adequate fuel storage facilities are provided.
e) Unit should have incorporated safety controls for low water, high pressure, ignition failure and overheating.
f) ' While planning the pipeline between the boiler and the heated space, ensure that the outgoing pipeline ditches in the direction of steam flow. The return pipe should ditch towards the condensation pump or the vacuum heating P-P .
Installation of Refrigerators
a) Ensure that shipment boards are removed before switching- on the machine.
b) Ensure that the machine is properly levelled. It is preferable to keep the machine on a wooden platform to prevent damage by floor moisture.
c) Check that the machine is not tcm close to the wall. Ensure proper circulation of cooling air around the unit.
d) Check the voltage variation and if necessary install a voltage stabilizer.
Electric Supply Switch Gear and Wiring
a) Check and ensure that voltage of electric supply is within permissible limits.If necessary a voltage stabilizer may be incorporated.
b) All electrical switch gear must be in accordance with IS1 specifications.
c) Wiring should be in conduits to ensure that an accidental short circuit will not set fire to the insulation.
d) All ends of the conduits should be properly sealed to prevent condensation of moisture.
e) Installation must conform to Indian Electricity Rules and nlust be done by a licensed contractor and qualified tradesman.
Heaters
a) Heaters may be installed ejther before the filters as preheater for the return air, in the ducts after the fan or in the base board heat units.
b) Heaters equipped with fins dissipate the heat quicker.
c) When heaters are used in the ducts or in the base board units, it is essential that fan is switched on before the heater is switched on. This is because otherwise the heater may develop excessive temperature and may either burn out or cause fire hazard; sequence controllers should be provided for this.
d) In case of basis-board, heaters should have a capillary tube to detect hot spots and turn off the heaters.
e) Manual switches should also be provided so that heaters can be switched off when not required.
f)Low voltage thermostat and relays should be provided for switching oWon the heaters. Direct switching will cause the thermostat to burn off due to heated contacts.
g) On account of frequent cycling, silent relays of bimetal or mercury switch type are preferable to open contact solenoid type.
Installation of Cooling Towers
a) Check that foundation is designed to take the load of the tower, its interior fill, basin and its water contents.
b) Locate the tower in such a way that it will not cause noise nuisance to nearby building. Preferably it should be on top of the plant room.
c) Check that the prevailing summer wind is in the same direction as the tower discharge air.
d) Ensure proper discharge connection to drainage to prevent flocdng of the surroundings.
e) To prevent loss of water by flocdng of the tower on shut down, the lower should be preferably placed above the condenser. Location on top of plant room will ensure this.
f)Check that adequate wind bracing is provided.
g) Drift eliminators should be provided to prevent carry over of entrained moisture.
h) Ensure that walkway is provided for facilitating maintenance of fan motor.
Water Softening Plant
a) Get the water tested for hardness. If the solid impurities contained are more than 200 ppm. water softening is necessary.
b) Ion exchange or acid treatment could he used for softening water. Acid treatment need careful control to avoid corrosion.
c) It is best to obtain advice from a specialist when water softening is considered necessary.
d) Use of hard water will create excessive scaling in the condenser tubes and make these ineffective.
a) Ensure that correct size of the conduit is used depending upon the s i ~ e and number of wires.
b) Ensure that all conduits are electrically connected to earth either by bonding at all joi* or by running a continuous earth wire of copper or GI.
c) Ensure that conduit ends have no sharp burrs as they damage the wires when pulled .through with a steel wire.
d) The boxes for switches, sockets etc should be fitted flush with the wall.
e) Ensure that conduit is fixed in the wall chasses with clamps and the chasses then filled with cement mortar before plastering the wall.
f)The wires through the conduits should be pulled straight and with uniform pull. It should. be done with steel flexible wire commc)nly
known as 'fish wire'.
g) After laying the conduit at the installation the conduit ends should be sealed against likely entry of water and cement slurry while plastering the wall.
C) Surface Conduit Wiring
a) Ensure that conduits are fitted properly in clamps and are not subjected to any load.
b) Earthing should be continuous and properly jointed at the joints.
c) All conduit boxes should be securely screwed and fitted with :heck nuts.
d) Ensure that conduits are laid straight and do not present unsightly appearance.
e) Surface conduits will be laid where authorised and will not be laid on plastered walls.
Earthing
a) Ensure that either an earthed terminal is provided by the supplier at the point of supply or the building has its own efficient earth so that all earth connections are connected to it.
b) Ensure that all non-current carrying metal parts of electrical fittings are connected with continuous earth wire to an independent earth except for those given in IE Rules Para 61 sub para 3 such as isolated wall bracket, switches etc.Earthing with gas pipes or water pipes is not allowed.
HVAC Works
Layout and Site Examination
a) On the layout plan of the building, mark out the locations and sizes of the impartant rooms and facilities so that there are no changes during execution.
These should include:
i)Plant room
ii) Weather making room
iii) Air handling units
iv) Cooling towers and water softening plant if provided. Where possible, these should be on top of the plant room.
v) Electric substation
vi) Water mains
vii) Drainagdsewers
viii) Stand by power house, if any
ix) Contractor's fabrication area
b) Check the sizes of the various plant rooms to ensure that these are adequate to house the plant and leave enough space for maintenance.
c) Check that available services like water, electricity, sewage are adequate. If not initiate action for their mcxiification.
d) Check that there will be no hold up during execution due to unforeseen site conditions.
Airconditioning Layout of Operation Theatre
a) In an operation theatre, recirculation of air is not permitted. Verify and ensure that proposed layout caters for this.
b) To ensure that contaminated air does not infiltrate into sterilized zone, check that layout provides for flow of air from operation theatre outwards to non-sterilized zone.
Coordination With Civil Engineering Works
a) Indicate on a plan the location and sizes of ducts diffusers and return gills.This should be given to the design section for incorporation in the plans.
b) Finalize the arrangements for fixing ducts so that necessary hwks etc can be left in the roof slabs where necessary.
c) Ensure that a time table is made out for handing over the various rooms to the a&conditioning contractor for installation of the equipment. Watch that this is adhered to.
iCPM Chart
Prepare CPM Chart for the airconditioning works and get it correlated with the CPM Chart of the building works. Review the chart periodically. Ensure that all activities are commenced and completed as planned.
Construction and Installation of Ducts
a) Sketch out the supply and return duct system
b) Indicate various sizes of duct sections, as per design
c) Fix location of outlet diffusers and return grills.
d) Check material for duct construction for quality and thickness
e) Ensure joints are made in accordance with IS: 655-1963 and reinforcement provided for rigidity.Inspect all branches, elbows etc before assembling.
g) After assembling, check seams and corners for air tightness. During construction, ensure that there are no sharp internal edges as these will generate noise.
h) Ensure that hanging arrangements are rigid and there is no strain on the joints.
i) Ensure dampers are installed in correct locations
j)Remember that fan, ducts, dampers, .diffusers return grill and return ducts form one correlated system. Change in any of these is likely to upset air balancing of the system.
k) When c~ossing walls, ensure that ducts are properly packed with felt/fiberglass to reduce noise and to prevent leakage from the room.
l) Ducts which are outside the conditioned space should be adequately insulated.Use vapour barrier to prevent moisture condensation inside the insulation materi d .
m) Bovide flexible canvas joints to prevent long duct system from vibrating like a string.
n) After final installation, check for vibration and noise at N1 design flow of air.
o) Large ducts should be provided with access doors for cleaning.
Installation of Chilled Water Mains
a) Ensure thorough internal cleaning of the pipes.Any lapse in this will cause serious damage to the system, as dirt will clog up the orifices, .
b) Check that suspension arrangements are as per design.
c) While fixing insulation, ensure that there is no moisture on the pipe.
d) After completing the installation, the following procedure should be gone through:
i)Bypass all controls and equipment with small tubes/c)rifices,
ii) Flush the pipeline with clear water till it appears to be clean.
iii) Load the system with 1 l b of trisodium phosphate to every 50 l b of water and circulate this by means of a pump for 8 hours.
iv) Then drain and flush with clean water.
v) Check with litmus papei the pH value; it should be 7.5. If high repeat the cleaning process and flush.
Check Lid
Location of Fresh Air Inlet
a) While locating the outside air inlet, ensure that surface dirt will not be drawn into the system.
b) Inlets taken above roof should be high enough to clear parapet walls.
c) Ensure that inlet is not in line with neighbourhood chimneys.
d) Inlet shciuld not be exposed to prevailing winter wind.
e) Ensure that proper louvers are provided at the inlet to keep out rain, birds and other objects.
Diffusion Devices
a) Check that conditioned air is not directly deflected towards an air return.
b) See that air flow does not strike walls, beams, or other obstructions.
c) See that no obstruction is placed in the air return passage.
d) Check that the adjustment of grill frets does not result in the supply air striking directly the thermostat.
e) Lowside wall or flush floor diffusers should be so adjusted that air is deflected properly upward for cooling and downward for heating.
Heading Furnaces
a) Check that adequate height of chimney is provided. The end of chimney should ,be protected by a hood.
b) Check that all the controls are tested before being installed.
c) Oil burners are meant to be used with a specified oil. Check the specification of the burner being provided. Inspect the test certificate which should normally be with the burner.
d) Ensure that adequate fuel storage is provided.e) See that unit incorporates safety control for temperature, ignition failure and over heating.
Heating Boilers
a) Check the manufacturer's data and verify that the boilers are according to the laid down specifications.
b) Ask for manufacturer's test certificate for the boiler working pressure. Boiler should be inspected by own bdler Inspector after the installation is completed and before it is commenced.
c) Check that Chimney height is adequate to produce the draft as laid down by
the makers.
d) Ensure adequate fuel storage facilities are provided.
e) Unit should have incorporated safety controls for low water, high pressure, ignition failure and overheating.
f) ' While planning the pipeline between the boiler and the heated space, ensure that the outgoing pipeline ditches in the direction of steam flow. The return pipe should ditch towards the condensation pump or the vacuum heating P-P .
Installation of Refrigerators
a) Ensure that shipment boards are removed before switching- on the machine.
b) Ensure that the machine is properly levelled. It is preferable to keep the machine on a wooden platform to prevent damage by floor moisture.
c) Check that the machine is not tcm close to the wall. Ensure proper circulation of cooling air around the unit.
d) Check the voltage variation and if necessary install a voltage stabilizer.
Electric Supply Switch Gear and Wiring
a) Check and ensure that voltage of electric supply is within permissible limits.If necessary a voltage stabilizer may be incorporated.
b) All electrical switch gear must be in accordance with IS1 specifications.
c) Wiring should be in conduits to ensure that an accidental short circuit will not set fire to the insulation.
d) All ends of the conduits should be properly sealed to prevent condensation of moisture.
e) Installation must conform to Indian Electricity Rules and nlust be done by a licensed contractor and qualified tradesman.
Heaters
a) Heaters may be installed ejther before the filters as preheater for the return air, in the ducts after the fan or in the base board heat units.
b) Heaters equipped with fins dissipate the heat quicker.
c) When heaters are used in the ducts or in the base board units, it is essential that fan is switched on before the heater is switched on. This is because otherwise the heater may develop excessive temperature and may either burn out or cause fire hazard; sequence controllers should be provided for this.
d) In case of basis-board, heaters should have a capillary tube to detect hot spots and turn off the heaters.
e) Manual switches should also be provided so that heaters can be switched off when not required.
f)Low voltage thermostat and relays should be provided for switching oWon the heaters. Direct switching will cause the thermostat to burn off due to heated contacts.
g) On account of frequent cycling, silent relays of bimetal or mercury switch type are preferable to open contact solenoid type.
Installation of Cooling Towers
a) Check that foundation is designed to take the load of the tower, its interior fill, basin and its water contents.
b) Locate the tower in such a way that it will not cause noise nuisance to nearby building. Preferably it should be on top of the plant room.
c) Check that the prevailing summer wind is in the same direction as the tower discharge air.
d) Ensure proper discharge connection to drainage to prevent flocdng of the surroundings.
e) To prevent loss of water by flocdng of the tower on shut down, the lower should be preferably placed above the condenser. Location on top of plant room will ensure this.
f)Check that adequate wind bracing is provided.
g) Drift eliminators should be provided to prevent carry over of entrained moisture.
h) Ensure that walkway is provided for facilitating maintenance of fan motor.
Water Softening Plant
a) Get the water tested for hardness. If the solid impurities contained are more than 200 ppm. water softening is necessary.
b) Ion exchange or acid treatment could he used for softening water. Acid treatment need careful control to avoid corrosion.
c) It is best to obtain advice from a specialist when water softening is considered necessary.
d) Use of hard water will create excessive scaling in the condenser tubes and make these ineffective.
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