40.2.3 Galvanized Iron (GI) Pipes and fittings
a. General: Galvanization shall conform to the requirement of BS 729. All threaded pipes and fittings shall have threads, in accordance with BS 21.
b. Pipes: The GI Pipe shall conform to the requirements of BS 1387: 1967. the Test pressure for all Classes (L, M and H) of GI Pipe shall be 700 psi.
c. Fitting: The material, wall thickness and galvanization quality, for the GI Fittings shall be same as that for the specified GI pipe.

40.2.4 Polyvinyl Chloride (PVC) pressure pipes and fittings:

Polyvinyl (PVC) pipes shall conform to the requirements of BS 3505:1968, for the specified class. The test and working pressures for various classes of pipes should be as under:
Class Test Pressure
Meter (Feet) Working pressure
Meter (Feet)
B 90 (300) 60 (200)
C 135 (450) 90 (300)
D 180 (600) 120 (400)
E 225 (750) 150 (500)

40.2.5 High Density Polyethylene (HDPE) Pipe & Fittings

All high density polyethylene pipes and fittings for installation at Chemical Dosing Facility shall be HDPE (High Density Polyethylene) conforming to ISO/ DIS 9969 with ring stiffness of 8kN/m2.



42.3 External Treatment for Piping

All underground GI and CI pipes and fittings shall be externally treated with one coat of hot applied bitumen (special industrial bitumen: 10 /20) and one layer of polythene sheet (500 microns) duly wrapped around.

42.4 VALVES AND APPURTENANCES

1. All valves shall be of same size as that of pipe line

2. Flow Control (Ball Type), check, float and foot valves of brass shall be installed on all the GI pipelines of water.

3. Cast Iron flanged gate valves (BS 5163, PN10 of approved make), metal seated wedge type with sealing ring and spindle of gunmetal shall be installed on all the wastewater and sludges pipe line.

4.Cast Iron (flanged) check valves (BS 5153, PN10 0f approved make) with swing type gun metal door shall be installed on all the wastewater and sludge pipelines.

All valves shall be tested to the appropriate test pressure at the manufacturer's works, and shall be supported by a test certificate from the manufacturer.

Markings of valves shall include the following:

• Manufacturing standard
• Manufacturer’s name or trademark
• Nominal diameter(s) (N.D) in mm
• Pressure rating in bars
• An individual serial number which relates directly to the manufacturer's test certificate
• Month and year of manufacture.

Position indicators shall be provided on all gate, butterfly and check valves.

The maximum effort required to operate the valve against the maximum unbalanced head applied at the circumference of the hand wheel or end of the tee-key shall not exceed 15 kN-m, where necessary gearing shall be provided as specified herein to achieve this.

Inspection, function test and strength test shall be made in accordance with DIN 3230 or approved equal.

The Contractor shall supply the original manufacturer's test certificate. The certificate shall relate to the individual number cast on each valve and shall give the date of test.

Valves shall be manufactured by an ISO 9000 series certified company who has had several years of experience in the manufacture of valves and shall have a fully equipped technical back-up and service facility. The manufacturer of the valves shall confirm the particular application of the valves for the intended use and shall provide a warranty of minimum 5 years on a replacement basis including labour and material at no extra cost. The warranty shall be issued directly to the Employer.

Before proceeding with any manufacturing, submit Shop Drawings for Engineer's prior written approval. Describe the items being submitted. Show dimensions, physical configurations, components and their composition, coating systems etc. Include material specification lists which shall summarize the specification features as called for in these Specifications and include such other necessary data as would provide a complete and adequate specification for re-ordering any spare part or an exact duplicate of the original from the manufacturer at some future date.