is_554

HINDUSTAN PETROLEUM CORPORATION LIMITED

GURU GOBIND SINGH REFINERY

PRODUCTS EVACUATION PROJECT

(GGSRPEP)

SPECIFICATIONS FOR PLUMBING WORK

0435-JH0902-00-AR-SPC-0004

C Issued for Tender

RAR

UDB

AK

06/06/09

B Issued for Client Review RAR UDB AK 29/05/09

A Issued for SDC RAR UDB AK 26/05/09

REV DESCRIPTION PREP CHECKED WORLEY- PARSONS APPROVAL

DATE HPCL APPROVAL

DATE


0435-JH0902-00-AR-SPC-0004 of 18

1. SCOPE This specification outlines the general requirements for supplying and laying of water supply pipe line with necessary fittings and fixtures for buildings/structures tapping of from potable water supply distribution system, supplying. Laying sewage pipe line with disposal works including provision of all fittings and fixtures of sanitary works and such other related items of work forming a part or the job, which may be required to be carried out though not specifically mentioned above. The work under this specification shall consist of furnishing of all tools, plants, labour, materials, and everything necessary for satisfactorily carrying out the work. 2. REFERENCE DOCUMENTS 2.1 Codes & Standards All work shall conform to the latest requirements of Indian Standards as listed below. Unless specified otherwise the International System of metric units (S.I.) is to be used. CODES IS: 458 Indian Standard Specification for Precast concrete pipes (with and Without reinforcements) IS: 554 Indian Standard Specification for Dimensions for pipe threads where pressure tight joints are required on the threads. IS: 651 Indian Standard Specification for Salt glazed stoneware pipes and fittings. IS: 774 Indian Standard Specification for Flushing cisterns for water closets and urinals (other than plastic cistern) IS: 775 Indian Standard Specification for Cast iron brackets and supports for wash basins and sinks. IS: 778 Indian Standard Specification for copper alloy gate, globe and check valves for water works purpose. IS: 781 Indian Standard Specification for cast copper alloy screw-down bib taps and stop taps for water services. IS: 783 Indian Standard Code of practice for laying of concrete pipes. IS 1068 Indian Standard Specification for Electroplated coatings of nickel and chromium and copper plus nickel plus chromium. IS: 1 172 Indian Standard Code of basic requirements for water supply, drainage and sanitation. IS: 1200 Indian Standard Specification for method of measurement of building and civil Engineering works - Part 16 & 19. IS: 1239 Indian Standard Specification for Mild steel tubes (Part – 1) and mild steel tubular and other wrought steel pipe fittings. (Part –2) IS 1536 Indian Standard Specification for Centrifugally cast (spun) iron pressure pipes for water, gas and sewage. IS 1626 Indian Standard Specification for Asbestos cement building pipes, gutters and fittings (spigot and socket types) Part-1 to Part-3. IS: 1703 Indian Standard Specification for Water fittings copper alloy float valves (horizontal plunger type). IS: 1726 Indian Standard Specification for Cast iron manhole covers and frames. IS: 1729 Indian Standard Specification for sand cast iron spigot and socket soil, waste and ventilating pipes, fittings and accessories. IS: 1742 Indian Standard Code of practice for building drainage.


0435-JH0902-00-AR-SPC-0004 of 18

IS: 2064 Indian Standard Code of practice for selection, installation and maintenance of sanitary appliances. IS: 2065 Indian Standard Code of practice for water supply in buildings IS: 2326 Indian Standard Specification for automatic flushing cisterns for urinals. IS: 2470 Indian Standard Code of practice for installation of septic tanks. Part- 1& 2 IS: 2527 Indian Standard Code of practice for fixing rain water gutters and down pipes for roof drainage. IS 2556 Indian Standard Specification for vitreous sanitary appliances. (Part 1 to Part 15) IS 2963 Indian Standard Specification for copper alloy waste fittings for wash basins and sink. IS: 3076 Indian Standard Specification for low density polyethylene pipes for potable water supplies. IS: 3114 Indian Standard Code of practice for laying of cast iron pipes. IS: 3311 Indian Standard Specification for waste plug and its accessories for sinks and wash basin. IS: 3486 Indian Standard Specification for cast iron spigot and socket drain pipes. IS: 4127 Indian Standard Code of practice for laying of glazed stoneware pipes. IS: 4984 Indian Standard Specification for high density polyethylene pipes for potable water supplies. IS: 5329 Indian Standard Code of practice for sanitary pipe work above ground for buildings. IS: 5434 Indian Standard Specification for Non-ferrous alloy bottle traps for marine use. 2.2 Other Standards / Specifications Specification of Earthwork, Concrete Work, Masonary Work Specification of Plumbing Specification of Drains and Sewers Conflict, if any, between this specification and related specifications, standards and documents shall be referred to the Engineer for resolution before proceeding with the work. 3. DRAWINGS All the drawings released for construction showing locations of sanitary and water supply fixtures shall be furnished to the contractor. Drawing will also furnish the details of one or more supply points outside the building for the water supply system and disposal point/scheme for sanitary works. The Contractor shall refer to these drawings for all information contained therein which pertains to details as required for this work. Contractor shall submit all detailed working drawings showing layout of water supply and sanitary works with necessary fittings and fixtures to Engineer-in-Charge for his approval, before the actual construction is undertaken. 4. WATER PIPELINES 4.1 Layout of Pipelines In addition to fulfilling the functional requirements, all pipelines shall be laid true to line, plumb and level. Any deviation shall be done with the Engineer-in-Charge's consent. Meticulous care shall be taken to avoid chances of airlock and water hammer. Pipes shall be laid on continuous unyielding surfaces or on reliable supports at least one new each joint and spacing as directed


0435-JH0902-00-AR-SPC-0004 of 18

by the Engineer-in-Charge. The support must be strong, neat and shall have provisions for securing the pipes in every direction and easy maintenance. Pipes shall be encased or concealed in masonry or concrete if shown on drawing or as directed by the Engineer-in-Charge. The layout of pipe work shall be such that there is no possibility of back flow towards the source of supply from any cistern or appliances, whether by siphonage or otherwise. All pipe works shall be so laid or fixed and maintained as to remain completely water tight, thereby avoiding waste of water, damage to property and risk of contamination of the water conveyed. There shall be no cross connection whatsoever between a pipe or fitting for conveying or containing wholesome water and a pipe or fitting for containing impure water or water liable to contamination or of uncertain quality of water which has been used for any purpose. No piping shall be laid or fixed so as to pass neither into nor through any sewer, scour outlet or drain or any manhole connected therewith. 4.2 Underground Piping It shall be laid at such a depth that it is not likely to be damaged by traffic and other loads and frost, where applicable. The size and depth of the trench shall be as approved by the Engineer-in-Charge. Backfilling shall be done with selected line earth, unless otherwise permitted, in 140 mm layers and carefully consolidated. Special care shall be taken while filling in the vicinity of the pipe to avoid damages. The pipes shall be cleared of all foreign matter before being laid. They shall be thoroughly brushed out with a well fitting hard brush, and after laying, the open end shall be temporarily plugged to prevent floatation of the pipes laid and flooding of trench. Before backfilling, the laid pipe shall be fully rested and approved by the Engineer-in-Charge. The laying of pipes shall comply with the procedure specified in Clause 9 of IS: 2064. 4.3 Jointing of Water Supply Pipes Jointing of pipes shall be completely leak proof and durable. The instructions of the manufacturer/Engineer-in-Charge shall be followed unless desired otherwise. The usual recommended practices are as mentioned below: i. Cast iron pipes The spigot and socket joints of CI pipes are usually caulked with lead. The jointing shall be in accordance with Clause 10.1 of IS 2065. ii. Flanged joints They shall also be done as per Clause 10.1.4 of IS: 2065. iii. Steel Plain-ended steel pipes may be jointed by welding. Screwed and socketed joints shall be carefully tightened. Care shall be taken to remove any burr from the ends of the pipes. Jointing compound, if used, shall be lead free and shall be approved by the Engineer-in-Charge. iv. Concrete Concrete pipes may be socket and spigot ended, collar or band jointed. Jointing shall be in accordance with the recommendations given in IS: 783. v. A.C. Pipes Socket and spigot ended pipes shall be jointed by caulking with tarred gasket and grouted with 1:2 cement sand mortar. vi. G.I. pes a) Screw socket joints


0435-JH0902-00-AR-SPC-0004 of 18

The screwed end of all GI pipes shall be thoroughly cleaned and painted with a mixture of red and white lead or Teflon before jointing, The joint shall be made of winding a few threads of hump round the ends of tubes and then screwing them into sockets to the full depth of threads. Exposed threads shall be bent/offset to save fittings. The offsets in GI pipes shall be made only after the permission of the Engineer-in-Charge. If threaded end of pipe is damaged, the Contractor shall cut the end with hacksaw and shall prepare new threads to required length. Threads shall be cut with sharp tools, and before jointing all scales shall be removed from pipes by suitable means. The screw threads of the pipe shall be cleaned out and the joint made by screwing the fittings alter treating the threads with approved pipe jointing compound. Once a joint has been screwed up, it shall not be backed off unless the threads are recleaned and new compound applied. b) Flanged joints Flanged joints shall be made by painting the faces or the flanges with red lead and halting up evenly on all sides with compressed asbestos gasket as per piping material specification. c) Valves Flanged or screwed valves shall be installed in locations shown on the drawings as per specifications for screwed or flanged joints. d) Lead Lead and lead alloy pipes shall be jointed with wiped solder joints. e) P.V.C. The instructions given by the manufacturer shall be followed. For heating, approved equipment with adequate control, shall be used. The work and materials shall be in accordance with IS: 3076 and IS 4984. 4.4 Inspection, Testing and Acceptance of Water Supply Lines All the pipes. fittings shall be inspected, before delivery at the site and tested after the installation and shall be in accordance with Clause 14 of IS:2065. 4.5 Painting Unless otherwise specified, underground steel and C.I. pipes shall be given 2 coats of bituminous paint on the outside after laying, when painting is to be done above ground. G.I. pipes shall be given a coat of zinc chromate primer. C.I. and M.S. pipes shall be given 1 coat of red lead or zinc chromate primer. Tap coats shall be minimum 2 coats of best quality enamel paint. 5. SANITARY INSTALLATION 5.1 General The work shall be carried out complying in all respects with any specific requirements of the local body in whose jurisdiction the work is situated, and as approved by the Engineer-in-Charge. All sanitary and plumbing work shall be carried out by licensed plumbers. All sanitary fittings and fixtures shall be acceptable to the Engineer-in-Charge & if there arc any variations, they shall satisfy the permissible tolerances in dimensions/slope/contour as specified in relevant IS codes/standards. All sanitary appliances including sanitary fittings, fixtures, toilet requisites shall be of size and design as specified in the item of work and as per sample approved by the Engineer-in-charge. All white glazed porcelain fixtures, such as wash basin, sink drain board, water closet pan, urinals. `P' trap etc. shall have hard durable white glazed Finish. They shall be free from


0435-JH0902-00-AR-SPC-0004 of 18

cracks, indentations, or other glazing defects. No chipped porcelain fixtures shall be used. Joints between iron and earthenware pipes shall be made perfectly air and watertight by caulking with neat cement mortar. The Contractor shall be responsible for any damage caused to the building, or to installations therein, either due to negligence on the part of the Contractor, or due to actual requirements of the work, they shall be made good and the building or the installation shall be restored to its original condition. The Contractor shall not be entitled for any extra payments for such works except when there is an item specifically included for such works in the schedule. On completion of the work the site shall be cleaned and disposed of all debris, as directed by the Engineer-in-Charge. 5.2 Laying and Lowering of Sanitary Lines Each separate pipe shall be individually set for line and level. Where lengths of sewer or drain pipes are laid in trenches, properly painted sight-rails shall be fixed across the trench at height, equal to length of the boring rod to be used, above the required invert level of the drain or sewer at the point where the sight is fixed. More sight-rails shall be required at manholes, changes of gradients and intermediate positions if the distance for sighting is more than 15.0m apart . The excavation shall be boned in at least once in every 1.8m. The foot of the boning rod shall be set on a block of wood of the exact thickness of the wall of the pipe. Each pipe shall be separately and accurately boned between sight-rails. The laying of pipes shall be in accordance with IS: 1742. Unless otherwise specified the minimum gradients of soil and drainage pipe line shall be as follows: Pipe Line Dia Gradient of Soil 100mm nominal dia 1 in 35 150mm nominal dia 1 in 65 230mm nominal dia 1 in 120 300mm nominal dia 1 in 200 For enter of the pipe lines into any building or structure, suitable conduits under the structure or sleeves shall be used. The conduits and sleeves shall be such as to allow easy repairs and replacement of the pipes. When openings or chases are required to be made in the structure for the entry of pipelines, locations and sizes shall be marked and checked by the Engineer-in-Charge. After laying of the pipe line, the openings and chases shall be mended. Where soil, waste and ventilating pipes are accommodated in ducts, access to cleaning areas shall be provided. Connection to drain shall be through a gully with sealed cover to be used against ingress of sewer gas, vermin or backflow. Pipes for carrying off the waste from water closets and wastewater and overflow water from baths, washbasins, sinks, drains shall be trapped immediately beneath such fixtures. Traps shall have minimum water seal of 50mm and shall be ventilated wherever such ventilation is necessary to maintain water seal of the trap. Ventilating pipes shall be carried up vertically from the drain to a height of at least 600mm above the outer covering of the roof of' the building or as shown on drawings. All vertical ventilating, anti- siphonage and similar pipes shall be covered on top with a cowl. The cowl shall be made of C.E. unless desired otherwise by the Engineer-in-Charge. i. The pipes shall be lowered when the trench is ready and the bottom has been properly

graded as per drawings.


0435-JH0902-00-AR-SPC-0004 of 18

ii. Lowering of the pipes shall be done as follows or as desired by Engineer-in-Charge. The pipes shall be inspected carefully. Broken or cracked pipe shall be rejected. The inside of the pipe shall be cleaned off with sand, earth or any other matter. iii. The pipe shall be lowered carefully so as not to distorts the bed and sides of the trench. Heavy pipes shall be lowered with chain pulley blocks or crane. Unless specifically cleared by the Engineer-in-Charge, under no circumstances shall special drainage and boil pipes be allowed to come close to water supply lines. 5.3 Support and Protection to Pipeline All pipes shall be laid with sockets leading uphill. Preferably the pipeline shall rest on solid and even foundations for the full length of the barrel. However, the pipe manufacturer's instruction as approved by the Engineer-in-Charge shall be followed regarding supporting and jointing of pipes. To achieve full and continuous support, concrete for bedding and packing is the best. Where pipes are not bedded on concrete. the floor shall be slightly high and carefully placed so that the pipe barrels rest on undisturbed ground. If anywhere the excavation has been carried too low packing shall be done in concrete. Where laid on rock or very hard ground which cannot be easily excavated to a smooth surface, the pipes shall be laid on a cradle of fine concrete floor of gravel and crushed stone over a well consolidated gravel and crushed stone bed as desired by the Engineer-in-Charge. PVC or similar pipes shall be laid directly on stable soil and packed with selected soil, The minimum support and protection for glazed stoneware pipes shall be as specified in IS: 1742. 5.4 Cutting and Jointing of Sanitary Pipes The instructions of the manufacturer shall be followed for cutting of the pipes where necessary. Suitable and approved tools shall be used for cutting so as to leave a surface a clean and square to the axis of the pipe. Jointing of laid pipes shall be so planned as to avoid completely any movement or strain to the joints already made. If any joint is suspected to be damaged it shall be opened out and redone. All joints between pipes, pipes and fittings and manholes shall be gas tight. The Engineer-in-Charge or the manufacturer shall lay down the instructions for the method of jointing the pipes and fittings conforming to relevant Indian Standards. Jointing Stone ware pipes with C.I. Pipes, Glazed Stone Ware pipes and RCC pipes shall be done as per IS: 1742. 5.5 Trenches and Other Excavations The width of the trench at the bottom shall be such as to provide 200mm clearance on either side of the pipe for facility of laying and jointing. Excavated material shall be stacked sufficiently away from the edge of the trench and the side of the soil bank shall not be allowed to endanger the stability of the excavation. Soil may be used for filling the trench behind the work or may be carted away as directed by the Engineer-in-Charge. 5.6 Inspection, Testing and Acceptance of Sanitary Lines All the pipes, fittings shall be inspected before delivery at the site and tested after the installation and shall be in accordance with IS: 1742. The pipeline shall be tested for water tightness of joints. In case joints are found to leak, they shall be repaired or redone and test shall be repeated until the joints are approved by Engineer-in-Charge. 5.7 Restoration of Damaged Surfaces and Clearing The Site


0435-JH0902-00-AR-SPC-0004 of 18

All pavements, structures, pipelines, cables etc., removed damaged or disturbed during the pipe laying work shall be restored to original conditions. 6. SANITARY FIXTURES 6.1 Indian Type Water Closet (LWC) This shall be the long pan pattern with separate footrests made of white glazed earthenware, white glazed vitreous china or of white glazed fire clay. The general requirements shall conform to IS: 2556 (Parts 3 & 10). Each pan shall have an integral flushing rim of suitable type. It shall have a peephole at the flushing inlet to the pan. The flushing inlet shall be in the front, unless otherwise specified or ordered by the Engineer-in-Charge. The inside of the bottom of pan shall have sufficient slope from the front towards the outlet and the surface shall be uniform and smooth to enable easy and quick disposal while flushing. The exterior surface shall be unglazed and sufficiently rough or grooved at right angles to the axis of the outlet. Pans shall be provided with a trap 'P' or "S' type with a minimum 50 mm water seal and 50mm dia, vent horn. Pan shall be laid at the correct location and level over a bed of lime concrete using brick aggregates (1 part lime mortar to 2 parts brick bats with lime mortar of 1 part lime to 2 parts of sand) or cement-sand admixture as specified in the drawings. 6.2 European Type Water Closet (EWC) Water closets shall be either of white glazed earthenware, white glazed vitreous china or white glazed fire clay as specified and shall be of "Siphonic Wash down type" conforming to IS: 2556 (Part 8). The closets shall be of one piece construction with approved plastic/bakelite seat and cover. Each water closet shall have 4 fixing holes having a minimum diameter of 6.5 mm for fixing to floor and shall have an integral flushing rim of suitable type. It shall also have an inlet or supply horn for connecting the flush pipe. The flushing rim and inlet shall be of the self draining two. The water closet shall have a weephole at the flushing inlet. Each water closet shall have an integral trap with either "S" or "P" outlet with at least 30 mm water seal. The water closets shall have an anti siphonage 50 mm dia. vent horn on the outlet side of the trap. The inside surface of water closets and traps shall be uniform and smooth in order to ensure an efficient flush. The serrated part of the outlet shall not be glazed externally. The water closet when scaled at the bottom of the trap in line with the back plate shall be capable of holding not less than 10 litres of water between the normal water level and the highest possible water level of the water closet installed. 6.3 Urinals

Urinals shall be of the bowl pattern, either flat back or angle back type lipped in front. They shall be of white glazed earthenware, white glazed vitreous china or white glazed fire clay, and of size as specified conforming to IS: 2556 (Part 6). The urinals shall be of one piece construction. Each urinal shall be provided with not less than two fixing holes of a minimum dia. of 6.5mm on each side. Each urinal shall have an integral flushing box rim of suitable type and inlet or supply horn for connecting the flush pipe. The flushing rim and inlet shall be of the self-draining type. It shall have a weep hole at tine flushing inlet of the urinal. At the bottom of the urinal, an outlet horn for connecting to an outlet pipe shall be provided. The exterior of the outlet horn shall not be glazed and the surface shall be provided with grooves at right angles to the axis of the outlet to facilitate fixing to the outlet pipe. The inside surface of the urinal shall be uniform and smooth throughout to ensure efficient flushing. The bottom of pan shall have sufficient slope from the front, towards the outlet such that there is efficient draining of the urinal, The waste fittings shall be chromium plated. 6.4 Wash Basins


0435-JH0902-00-AR-SPC-0004 of 18

Wash basins shall be of white glazed earthenware, white glazed vitreous china or white glazed tile clay as specified and confirming to IS: 2556 (Part 4) Type Size Flat Back 630 x 450 mm Flat Back 550 x 400 mm Wash basins shall be of one piece construction, including a combined overflow. All internal angles shall be designed so as to facilitate cleaning. Each basin shall have a min. sloping inside towards the bowl on all sides except sides in contact with the walls and shall have skirting at the back. Basins shall be provided with single or double tap holes as specified. The tap holes shall be square. A suitable tap hole button shall be supplied if one tap hole is not required in installation. Each basin shall have a circular waste hole to which the interior of basin shall drain. The waste hole shall be either rebated or beveled internally with diameter of 65 mm at top and a depth of 10 mm to suit a waste plug having 64 mm diameter. Each basin shall be provided with a non-ferrous 32 mm waste fitting. Stud slots to receive the brackets on the underside of the wash basins shall be suitable for a bracket with stud not exceeding 13 mm diameter. 5 mm high and 305 mm from the back of basin to the centre of the stud. The stud slots shall be of depth sufficient to take 5 mm stud. Every basin shall have an integral soap holder recess or recesses which shall fully drain into the bowl. The position of the chain stay-hole shall not be lower than the overflow slot. A slot type of overflow having an area of not less than 500 sq.mm. shall be provided and shall be so designed as to facilitate cleaning of the overflow. The specifications for waste plug, chain and stay shall be the same as given for sinks. All the waste fittings shall be chromium plated. Bottle trap shall conform to IS: 5434. The chromium plating shall be of service grade No.2 conforming to IS: 1068. 6.5 Sinks The sinks shall be white glazed earthenware, white glazed vitreous china or white glazed fire clay as specified conforming to IS: 2556 (Part 5) and shall be of the following sizes : 450 x 300 x 150 mm, 600 x 450 x 200 mm All sinks shall be of one piece construction, including a combined overflow. The floor of the sink shall gently slope towards the outlet. The outlet shall in all cases be suitable for waste fittings having flange of 64 mm diameter and the waste hole shall have a minimum diameter of 65 mm at the bottom to suit the waste fittings. The water hole shall be either rebated or beveled having a depth of 10 mm. Each sink shall be provided with a non-ferrous 40 mm dia. waste fitting. The sink shall have overflow of weir type and the inverts shall be 30 mm below the top edge. Each sink shall be provided with a waste plug, of suitable dia. chain and stay. The plug shall be of rubber or other equally suitable material and shall be watertight when fitted. Plug chains shall be of brass wire chromium plated. It shall have an overall length from the collar to the stay of not less than 300 mm. There shall be a triangular or D shackle at each end, one of which shall be braced to the plug and the other securely fixed to the stay. The 150 mm long shank of the waste shall be threaded conforming to the requirements of IS:2556 for sinks only. The waste fittings and plug fittings shall be chromium plated. The chromium plating shall be of service grade No.2 conforming to IS: 1068. 6.6 Stop Cock and Bib Cock A bibcock (bib trap) is a draw off tap with a horizontal inlet and free outlet and stopcock (stop tap) is a valve with a suitable means of connections for insertion in a pipe line for controlling or stopping the flow. They shall be of sped fled size and shall be of the screw down type. The closing device should work by means of a disc carrying a renewable non-metallic washer,


0435-JH0902-00-AR-SPC-0004 of 18

which shuts against water pressure on a seating at right angles to the axis of the threaded spindle which operates it. The handle shall be either crutch butterfly type securely fixed to the spindle. The cocks shall open in anti-clockwise direction. When the bib cocks and stop cocks are required to be chromium plated. the chromium plating shall be of service Grade No.2 conforming to IS: 1068. In finish and appearance, the plated articles shall be free from plating shall not be stained or discoloured. These fittings shall be of brass heavy class, chromium plated (C.P) and of approved manufacture and pattern with screwed or flanged ends as specified. The fittings shall in all respects be in accordance with the requirements of IS: 781. The standard size of brass fittings shall be designated by the nominal bore of the pipe to which the fittings are attached. A sample of each kind of fitting shall be got approved from the Engineer-in-Charge and all supplies made according to the approved samples. All cast fittings shall be sound and free from laps, blow holes and fittings, the internal and external surfaces shall be clean, smooth and free from sand etc. Burning, plugging stopping or patching of the casting shall not be permitted. The bodies, bonnets, spindles and other pans shall be truly machined and when assembled the parts shall be axial, parallel and cylindrical with surfaces smoothly finished. The area of the water way of the fittings shall not be less than the area of the nominal bore. The fittings shall be fully examined and cleared of all foreign matter before being fixed. The fittings shall be fitted in the pipeIine in a workman like manner. The joints between fittings and pipes shall be made leak-proof. The joints and fittings shall be leak proof when subjected to a pressure test specified by the Engineer-in-Charge and the defective fittings and joints shall be replaced or redone. 6.7 Flushing Cisterns The flushing cisterns shall be either operated manually or automatic, high level or low level, as specified. For water closets and urinals high level cistern is intended to operate with minimum height of 1.25m and a low level cistern with a maximum height of 300mm between the top of the pan and the underside of the cistern. They shall be of cast iron, glazed earthenware, or pressed steel complying with the requirement of IS 774. Automatic flushing cistern for urinals shall conform to IS: 2326. 6.8 H.C.I Nahni Trap (Floor Trap) Nahni trap shall be of heavy cast iron as per IS: 3989 with 100mm inlet and 80/100mm outlet with C.P pressed steel grating. It shall be of self cleaning design (grating shall be of either hinged or screwed down type). It shall be fixed in cement mortar 1:2 and as directed by Engineer-in-Charge. 7. CAST IRON SOIL WASTE AND VENT PIPES AND FITTINGS All cast iron pipes and fittings shall be of uniform thickness with strong and deep sockets, free from flaws, air holes, cracks, sand holes and other defects and conform to IS: 1536. The diameter specified shall be internal diameter of pipe. The pipes and fittings shall be true to shape, smooth and cylindrical and shall ring clearly when struck over with a light hand hammer. All pipes and fittings shall be properly cleaned of all foreign material before being fixed. All plug bends of drainage pipes shall be provided with inspection and cleaning caps, covers, which shall be fixed with nuts and screws. Pipes shall be fixed to the wall by WI, or M.S. holder bat clamps, unless projecting ears with fixing holes are provided at socket end of pipe. The pipes shall be installed, truly vertical or to the lines and slopes as indicated. The clamps shall be fixed to the walls by embedding their hooks in cement concrete blocks (1:2:4) 100mm x 100mm by making necessary holes in the walls at proper places. All holes and breakages shall be made good. The clamps shall be kept 25 mm clear of the finished face of the walls to facilitate cleaning and painting of pipes. The annular space between the socket and spigot shall be filled with a gasket of hemp or spun yarn soaked in neat cement shiny. The joint shall then be filled with stiff cement mortar 1:2 (1: cement : 2 fine sand) well pressed with caulking tool and finished smooth on top at an angle


0435-JH0902-00-AR-SPC-0004 of 18

of 45°. The joint shall be kept wet for not less than a week by lying a piece of gunny bag kept moist. Joints shall be both air tight and water tight. C.I. pipes and fittings, which are exposed, shall be first cleaned and then painted with a coat of red lead primer. Two coats of zinc paint with white base and mixed with pigment of required color to get the approved shade shall be given over the base primer coat. The thickness of fittings and their socket and spigot dimensions shall conform to the thickness and dimensions specified for the corresponding sizes of straight Pipes. The connection between the main pipe and branch pipes shall be made by using branches and bends with access for cleaning. Floor traps shall be provided with 25 mm dia puff pipe where the length of the waste is more than 1.80m or it shall be connected to a waste stack through bends. C.I. pipes shall be measured along the centre lines of pipes including fittings such as branches, plug, bends, etc. All C.I. pipes and fittings including joints shall be tested by a smoke test to the satisfaction of the Engineer-in-Charge and left in working condition after completion. The smoke test shall be carried out as mentioned below. Smoke shall be pumped into the pipe at the lowest end from a smoke machine, which consists of a blower and a burner. The material usually burnt is greasy cotton waste, which gives out a clear pungent smoke, which is easily detectable by sight as well as by smell if there is a leak at any point of the pipeline. Water and air tests shall be conducted as per IS: 5329. All C.I pipes shall be painted with two coats of anticorrosive bituminous paint externally. 8. ASBESTOS CEMENT PIPES AND FITTINGS All A.C. soil, waste, vent pipes, and fittings shall conform to IS:1626. The pipes shall have spigot and socket ends. These shall be composed of an inert aggregate consisting of clean asbestos fibre cemented together by ordinary Portland cement conforming to IS: 269, or Portland blast furnace slag cement conforming to IS:455. No organic material shall be added to the composition. All pipes shall be straight and the ends of the pipes and fittings shall be finished square to their axes, The finished pipes and fittings shall be true and smooth, their inner and outer surfaces shall be concentric. They shall be in all respects sound, homogenous and free from impurities or other imperfections. The permissible tolerances on the thickness and external dimensions of pipes and fittings including hydraulic test pressure of the pipes and fittings shall conform to IS:1626. All A.C. pipes and fittings shall be of approved make and with necessary accessories, wherever required. The diameter wherever specified for pipes and fittings shall be clear internal diameter. All gaps between pipes and fittings and walls shall be filled with cement mortar 1:3 neatly finished for which no extra payment will be made. All pipes and fittings shall be supported with standard fixing brackets. The annular space between the socket and spigot shall be filled with a gasket of hemp or spun yarn soaked in tar. The joint shall then be filled with stiff cement mortar 1:2 (1 cement : 2 find sand) well pressed with caulking tool and finished smooth on top with neat cement paste at an angle of 45°. The joint shall be kept wet for not less than a week by tying a piece of gunny bag kept moist. Joints shall be both air-tight and water-tight. A.C. pipes shall be measured along the centre lines of pipes including fittings such as junctions, bends, etc. Pipes and fittings shall be tested with a smoke test. 9. G.I. PIPES AND FITTINGS All pipes shall be galvanized mild steel welded pipes and seamless screwed and socketed tubes conforming to the requirements of IS 1239, for medium grade. They shall be of the diameter (nominal bore) specified in the description of the item. The sockets shall be designated by the respective nominal bores of the pipes for which they are intended. The pipes and sockets shall be finished neatly, well galvanised on both inner and outer surfaces. and shall


0435-JH0902-00-AR-SPC-0004 of 18

be free from cracks, surface flaws, laminations and other defects. All screws, threads shall be clean and well cut. The ends shall be cut cleanly and square with the axis of the tube. All screwed tubes and sockets shall have pipe threads conforming to the requirements of IS: 554. Sockets shall have parallel threads. The fittings shall be of malleable C.I. or mild steel tubes complying with all the appropriate requirements as specified for pipes. The fittings shall be designated by the respective nominal bores of the pipes for which they are intended. The fittings shall have screw threads at the ends conforming to the requirements of IS: 554. Female threads on fittings shall be parallel and male threads (except on running nipples and collars of unions) shall be tapered. All the pipes and fittings shall be inspected at site before use to ascertain that they conform to the specification. All the defective pipes shall be rejected. Where the pipes have to be cut/rethreaded, the ends shall be carefully filled out so that no obstruction to bore is offered. The ends of the pipes shall then be threaded conforming to the requirements of IS: 354 with pile dies and taps carefully without any slackness of joints when the two pieces are screwed together. The laps and dies shall be used only for straightening bent and damaged screw threads and shall not be used for turning of the threads so as to make them slack, as the latter procedure may not result in a water tight joint. The screw threads of pipes and fitting shall be protected from damage until they are fitted. The pipes shall be cleaned and cleared of all foreign matter before being laid. In jointing the pipes, the inside of the socket and the screwed end of the pipes shall be oiled and rubbed over with white lead and a few turns of spun yarn wrapped around the screwed end of the pipe. The end shall then be screwed in the socket, tee etc., with the pipe wrench. Care should be taken that all pipes and fittings arc properly jointed so as to make the joints completely water tight and pipes are kept at all time free from dust and dirt during fixing. Burrs from the joint shall be removed after screwing. After laying, the open ends of the pipes shall be temporarily plugged to prevent access of soil or any other foreign matter. Any threads exposed after jointing shall be painted or in the case of underground piping thickly coated with approved anti corrosive paint to prevent corrosion. For internal work the galvanised iron pipes and fittings shall run on the surface of the walls or ceiling (not in chase) unless otherwise specified, The fixing shall be done by means of standard pattern holder bat clamps, keeping the pipes about 15mm clear of the wall. Pipes and fillings shall be fixed truly vertical/horizontal. Wherever necessary. to conceal the pipes, chasing may be adopted or pipes fixed in the ducts of recesses etc. provided, there is sufficient space to work on the pipes with the usual tools. The pipes shall not ordinarily be buried in walls or solid floors. Where unavoidable, pipes may be buried for short distances provided adequate protection is given against damage, but the joints in pipes shall not be buried. Where directed by the Engineer-in-Charge, a M.S. pipe sleeve shall be fixed at a place where a pipe is passing through a wall or floor for reception of the pipe and to allow freedom for expansion/contraction and other

pavements' maintenance. All pipes embedded in walls or floors shall be painted with anti-corrosive bitumastic paint of approved quality. No pipe shall come in contact with lime mortar or lime concrete as the pipe is affected by lime. Under the floors the pipes shall be laid in layer of sand filling or as directed by the Engineer-in-Charge. G.I. pipes with socket and spigot ends shall be provided with lead caulked joints wherever specified and the joints shall conform to the requirements of IS: 3114. The work of excavation and backfilling shall be done true to line and gradient in accordance with general specifications for earth work in trenches for pipes laid underground. All the pipes shall be laid on a layer of 75mm sand and filled upto 150mtr above the pipes. The remaining portion of the trench shall then be filled with excavated earth. The surplus earth shall be disposed of as directed. When excavation is done in rock the bottom shall be cut deep enough to permit the pipes to be laid on a cushion of sand 75mm minimum. All underground pipes shall have a minimum earth lower of 600mm or as directed by the Engineer-in-Charge. All the pipelines shall be subjected to hydrostatic pressure test as specified by the Engineer-in-


0435-JH0902-00-AR-SPC-0004 of 18

Charge and shall satisfactorily pass the test. Pipeline system shall be tested in sections as the work proceeds, keeping the joints exposed for inspection. Pipes shall be slowly and carefully charged with water allowing all air to escape. All draw off taps shall then be closed and water pressure gradually raised to test pressure. Accurate and calibrated pressure gauge shall be used for pressure gauging. The section of the pipeline shall maintain the test pressure for at least half an hour, after stopping the water pump. Any leaking joints/pipes found shall be removed and replaced by the Contractor without any extra cost. The G.I. pipeline shall be cut to the required length at the position where the meter and stop cock arc required to be fixed. The ends of the pipes shall be threaded. The meter and stopcock shall be fixed in position by means of connecting pipe, G.I. nuts, sockets, etc. The stopcock shall be fixed near the inlet of the water meter. The paper disc inserted in the ripples of the meter shall be removed and meter installed exactly horizontally or vertically and with the arrow cast on the body of the meter pointing in the direction of flow. Care shall be taken that the factory seal of the meter is not disturbed. Whenever the meter is to be fixed to a newly fitted pipeline, the pipeline shall be completely washed before fixing the meter. For this purpose, a connecting piece of pipe equal to the length of the meter is to be fixed on the new pipeline. The water shall be allowed to flow completely to wash the pipeline and then the meter installed as described above by replacing the connecting piece. G.I. pipes with fittings completely fixed in position shall be measured and paid for, based on the finished centre line lengths. GUN METAL VALVE All full way and globe valves shall be heavy gun metal and tested at 300 psi and shall be approved by the Engineer-in-Charge. Valves shall conform to IS: 778. Size of valve chamber shall be as per the clause 15, valve chamber shall be provided and fixed with heavy duty C.I. surface box conforming to IS: 3950. The surface box shall be hinged pin open type and shall be fixed in the chamber slab. It shall have a hole for opening. 10. STONEWARE PIPES AND FITTINGS All pipes with spigot and socket ends shall conform to IS: 651 and shall be of grade 'A' as specified. These shall be sound, free from visible defects such as fine cracks or hair cracks. The pipes shall give a sharp clear tone when struck with a light hammer. There shall be no broken blisters. The pipe shall be handled with sufficient care to avoid damage to them. Pipes shall be laid to the correct grade and alignment shown in the plan/sections with their sockets up the gradient. Laying and jointing shall conform to the general requirements specified in IS: 651 Stoneware pipes used for sewers shall be subjected to a test pressure of 1.5m head of water at the highest point of the section under test. The test shall be carried out suitably by plugging the low end of the drain and the ends of the connection if any and filling the system with water. A buckle bend shall be temporarily jointed in at the top end and a sufficient length of vertical pipe jointed to it so as to provide the required test head or the top may be plugged with a connection to a hose ending in a funnel which could be raised or lowered till the required head is obtained and fixed suitably for observation. Wherever leakages are detected, the defective part of the work shall be removed and made good. In measuring the length of sewer pipes, laid length between faces of manholes shall only be measured deducting lengths of channels between inside faces of walls of manholes or chambers. 11. RCC PIPES AND FITTINGS All RC pipes shall conform to IS: 458 - For material specification refer respective standard specifications. All pipes must be perfectly sound, straight and of standard nominal diameter and length with even texture. Each pipe shall have one collar with it. The annular space between the socket and spigot shall be filled with a gasket of hemp or spun yarn soaked in tar. The joint shall then be lined with stiff cement mortar 1:2 (1 cement : 2 fine sand) well pressed with caulking tool and finished smooth on top with neat cement paste at


0435-JH0902-00-AR-SPC-0004 of 18

an angle of 45. The joint shall be kept wet for not less than a week by tying a piece of gunny bag kept moist, Joints shall be both air-tight and water-tight. The laying of jointing of pipe shall conform to IS: 783. The trench shall be checked for proper level, gradient and alignment before lowering the pipes. Pipes and fittings shall be tested with a smoke test. 12. RAIN WATER DOWN CORNERS

They shall be of standard 150mm dia rigid PVC pipes (6 kg/m2 rating), or as specified. All pipes shall be of approved make with standard M.S. fixing clamps including special fittings such as bends, shoes, junctions, swan - necks etc. confirming to general requirement of IS: 2527. Rainwater down corners shall run along and be secured to walls, columns etc. Where desired by the Engineer-in-Charge these may have to be installed in chases cut in the structures, All pipes shall be well secured and supported by adequately strong brackets. The brackets may be wrought iron cleaves type, split ring type or perforated strap iron type as approved by the Engineer-in-Charge. For vertical runs each pipe shall be hung freely on its bracket. fixed just below the socket. Suitable spacer blocks shall be provided against the vertical surface to which the pipe is fixed. All bends and junctions shall be supplied with water tight clean outs. Roof and floor drains and yard gullies shall be installed, if required, by cutting into the structure and grouted with 1:2:4 cement concrete. All gutters shall be provided with removable gratings. All horizontal pipes shall have a minimum gradient of 1 in 100 (min.). 13. GUTTERS The gutters shall be made of G.l. or A.C. All glitters shall be supplied by renowned manufactures. Each section shall be sufficiently rigid. edges and corners straight and the slopes perfectly uniform. The GA. gutters shall have the edges strengthened by suitable means. Unless noted otherwise the glitters shall have a minimum gradient of 1 in 120. Adequate number of strong supports shall be provided so that there is no deflection even when the gutter is full. Each joint must have a support. Unless otherwise specified the supports shall be fabricated MS brackets. All junctions shall be thoroughly watertight. The joints may be made by riveting bolting or soldering. All joints between successive lengths of gutters shall have an overlap of at least 50mm. The drop in the overlay shall always be in the direction of the fall of the gutter. Ends of the gutters shall be closed watertight. Junction with rain water down corners shall be made fully watertight and secured. 14. SOAK PIT Soak pit shall be constructed as detailed in working drawings at the location as directed by the Engineer-in-Charge. Earthwork excavation shall be carried out to the exact dimensions. Brick masonry lining with open joints shall be constructed in the pit up to 150 mm below the outlet pipeline. Brick masonry in cement mortar 1:6 shall be constructed above this level up to ground. Well burnt brick aggregates of nominal size 40 mm to 80 mm and coarse sand shall be filled within the chamber. Construction of pit lining and filling of the brick ballast shall progress simultaneously. 15. MANHOLES/INSPECTION CHAMBER AND VALVE CHAMBER Manholes and valve chambers shall be constructed in the sewer line at such places and to such level end dimensions as shown in the drawings or as directed by the Engineer-in-Charge. The size specified indicate the inside dimensions of the manhole. Excavation and hack filling shall be as per Standard Specification For Site clearing. Area grading, Excavation and Earthwork,


0435-JH0902-00-AR-SPC-0004 of 18

Manhole shall be built on a bed of cement concrete 1:4:8 (1 cement : 4 sand : 8 graded stone aggregate of 40 mm nominal size). The thickness of the bed concrete shall be 230mm unless otherwise specified or directed by the Engineer-in-Charge. In bad ground special foundation shall be provided. The inside and outside face of the masonry wall shall be plastered with 13mm thick plaster of CM 1:3. Brick work shall be with first class country bricks in cement mortar 1:3 (1 cement: 3 sand). The external joints of the brick masonry shall be finished smooth. The joints of the pipes with the masonry shall be made perfectly leak-proof. All brickwork shall be carried but as per IS: 2212. The brick walls of the manholes shall be plastered inside with 15 mm thick cement plaster 1:3 (1 cement: 3 sand) finished smooth with a floating coat of neat cement. Channels and benching shall be in cement concrete 1 : 2 : 4 ( 1 cement : 2 sand : 4 graded stone aggregate). The channel or drain at the bottom of the chamber shall be plastered with cement mortar of 1:2 proportion and finished smooth, to the grade (where required). The depth of channels and benching shall be as indicated in the table given below:

Size of drain

Top of channel at the centre above bed concrete

Depth of benching at side walls above bed concrete

mm

mms mms

10

150 200

15

200 300

20

250 350

25

300 400

30

350 450

35

400 500

40

450 550

45

500 600

All manholes deeper than 800mm m shall be provided with staggered M.S. rungs as specified in drawings. Rungs shall be painted with coal tar, the portion embedded in cement concrete block being painted with thick cement slurry before fixing. All C.I. manhole covers and frames shall conform to IS: 1726. The covers and frames shall be neatly cast and they shall be free from air and sand holes and from cold shuts. They shall be neatly dressed and carefully trimmed. All casting shall be free from voids whether due to shrinkage or other causes. Cover shall have a raised chequered design on the top surface to provide an adequate non-slip grip, The cover shall be capable of easy opening and closing and it shall be correctly fitted in the frame. The cover shall be coated with a black bituminous composition. It shall not flow when exposed to a temperature of 63°C and shall not be brittle as to chip off at temperature of 0ºC. The frame of the manhole cover shall be firmly embedded to correct alignment and levels in plain cement concrete 1:2:4 (1 cement : 2 sand : 4 graded stone aggregate) on top of the brick masonry, After completion of the work, manhole covers shall be smeared with thick -grease. Manhole cover and frame shall conform to "Medium Duty ", 500 mm internal diameter and shall weigh not less than 116 kg. (weight of cover 58 kg. and weight of frame 58 kg) Manholes shall be measured in numbers. The depth of the manhole shall be reckoned from top level of C.l. cover to the invert level of channel. The depth shall be measured correct to mms. Inspection chambers shall be constructed similar to manholes as detailed in working drawings. Sewers of unequal sectional area shall not be jointed at the same invert level in a manhole. The


0435-JH0902-00-AR-SPC-0004 of 18

invert of the smaller sewer at its junction with main shall be at least 2/3 the diameter of the main, above the invert of the main. The branch sewer should deliver sewage in the manhole in the direction of main flow and the junction must be made with care so that flow in the main is not impeded, No drains from house fittings e.g. gully trap or soil pipe etc. to manhole shall normally exceed a length of 6 metres unless it is unavoidable. The specification for brick masonry, plastering, concreting, excavation and backfilling as given under relevant clauses shall be applicable for this work also. 16. DROP CONNECTION In cases where branch sewer enters the manholes of main pipe sewer at a higher level than the main sewer, a drop connection should be provided. Pipes and specials conforming to IS: 1729 shall be of the same size as the branch pipe sewer. For 150 mm and 250 mm main line, if the difference in level between the water line (peak flow level) and the invert level of branch line is less than 600mm, a drop connection may be provided within the manhole by giving a suitable ramp. If the difference in level is more than 600mm the drop should be provided externally. The excavation shall be done for the drop connection at the place where the branch line meets the manhole. The excavation shall be carried up to the bed concrete of the manholes and to the full width of the branch line. Excavation and backfilling shall be done as per Standard Specification. At the end of branch sewer line C.I. tee shall be fixed to the line which shall be extended through the wall of manhole by a horizontal piece of C.I. pipe to form an inspection or cleaning eye. The C.I. drop pipe shall be connected to the tee at the top and to the C.l. bend at the bottom. The bend shall be extended through the wall of the manhole by a piece of pipe which shall discharge into the channel. Necessary channel shall be made with cement concrete of grade M15 and finished smooth to connect the main channel. The joint between C.I. pipe and fittings shall be lead caulked. The joint between C.I. tee and S.V. branch line shall be made with cement mortar 1:1 (1 cement : 1 find sand). The exposed portion of the drop connection shall be encased around with minimum 150mm. thick concrete 1:5:10 (1 cement : 5 coarse sand : 10 graded stone aggregate 40 mm nominal size) and cured. For encasing the concrete around the drop connection, necessary centring and shattering shall be provided. The holes made in the walls of the manhole shall be made good with brickwork in cement mortar 1:4 (1 cement: 4 coarse sand) and plastered with cement mortar 1:2 (1 cement: 2 fine sand) on the inside of the manhole wall. The excavated earth shall be back filled in the trench in level with the original ground level. Drop connection shall be measured in numbers. 17. ROAD GULLY CHAMBERS The chamber shall be of brick masonry/RCC and shall have a C.I. grating with frame fixed in 150 mm thick cement concrete of grade M15 at the top. The size of the chamber shall be taken as clear internal dimensions of the C.I. frame. The chamber shall have a S.W. connection pipe, the length of which between road gully chamber and the point of discharge to drain or to open ground shall be measured separately. The chamber shall be built at the locations indicated in drawings. Bed concrete, brick work plastering, R.CC work, excavation, back filling, etc. shall be as per details given on the drawing and in compliance with the requirements laid down in the specifications for the respective items. The gully grating cover shall be hinged to the frame to facilitate its opening for cleaning and repairs. The weight of grating shall be 75 kg. minimum. After completion of the work, the exposed surfaces of the grating and the frame shall be painted with a thick coat of coal tar. The square mouth gully trap shall be 100mm dia conforming to IS: 651 of specified and/or approved quality material. Complete work CI grating and shall be got approved by the Engineer-in-Charge. The size of Cl frame and shall be 300mm x 300mm. 18. MISCELLANEOUS ITEMS


0435-JH0902-00-AR-SPC-0004 of 18

18.1 M.s. Rungs/C.I. Steps The rungs for pits/manholes and septic tanks shall be of M.S conforming to Indian Standard and to the shape and size as shown in drawings. CI steps for manholes if needed shall be as per IS: 5455. MS rungs shall be coated with approved bituminous paint. 18.2 C.L Manhole Frame and Cover C.I manhole frame and covers shall conform to IS: 1726 with size and grade as shown in drawings. 18.3 Vent Pipes These shall be M.S black steel tube conforming to IS: 1239 or as specified in drawings, the pipe bends shall be embedded in 1:3:5 grade cement concrete. All pipe shall be 25mm clear of wall or column with M.S holder bat clamp. All holes in walls shall be made good by 1:2:4 grade cement concrete. All pipes and clamps shall be painted with two coats of paint of approved make. 18.4 Funnels, Cleanouts, Plugs These shall be fabricated from M.S plates, chequered plate around angles etc. The fabrication shall be in accordance with approved drawings. Connection of funnel/clean out/plugs where necessary shall be made with resin cement mixed with finely ground grade of a pipe material. Payment for these items shall be made on weight basis and shall include fabrication, erection, welding jointing and painting etc., all complete. 18.5 Cast Iron Grating The CI grating and frame shall conform to IS: 5961. The casting shall be clearly cast and free from air sand shrinkage, gas inclusion or any other holes with carefully dressed sides. The grating cover shall be hinged to frame to facilitate its easy opening and closing for repairs of manholes/catch pits etc. 19. SEPTIC TANK Hume pipe septic tank and accessories shall be horizontal type of standard manufacture as approved by the Engineer-in-Charge. Septic tank shall be installed exactly as per manufacturer's requirements and instructions at locations indicated by the Engineer-in-Charge. 230 mm thick and 500 mm internal diameter brick manhole shall be constructed up to grade level and covered with 500 mm circular medium duty cast iron frame and cover. Internal face of brickwork shall be plastered with 13 mm thick cement mortar 1:3. 20. FIRE HYDRANTS The hydrant shall be fully examined and cleared of all foreign matter before being fixed. The fixing shall be done on the water main which shall be of minimum 80mm dia. The flanged end of the hydrant shall be fixed to the flanged outlet of a tee in the water main by means of bolts and nuts. This can also be fixed by means of flanged tail piece which may be connected to the water main by C.I. fittings. 21. GUARANTEE FOR WATER SUPPLY SOIL & VENT SYSTEMS


0435-JH0902-00-AR-SPC-0004 of 18

The Contractor shall deliver to the Engineer-in-Charge upon completion of his work under this contract, a written guarantee that : i) For a period of one (1) year after acceptance by the Engineer-in-Charge, plumbing and drainage work shall be free from defective material and workmanship. ii) For a period of one (1) year after acceptance by the Engineer-in-Charge, the Contractor shall be responsible for the water/air tightness of all joints. iii) He will, at his own expense, repair, replace all such defective work and all other works damaged thereby, during the term of guarantee. After completion of the work, the Contractor shall obtain and hand over to the Engineer-in-Charge necessary certificates. 22. CONNECTION TO AN EXISTING SEWER The connection to an existing sewer shall as far as possible, be done at manholes. Where it is unavoidable to make the connection in between two manholes, the work of breaking into the existing sewer and forming the connection shall be carried out under the supervision of the Engineer-in-Charge. Breaking into the sewer shall be effected by the cautions enlargement of a sewer hole and every precaution shall be taken to prevent any material from entering the sewer. No connection shall be formed in such a way so as to constitute a projection into the sewer or to cause any diminutions in its effective size.