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DI Fittings & Valves Checklist for Water Transmission Bids

  • Writer: Pipekom
    Pipekom
  • Sep 10
  • 3 min read

Water transmission projects — whether municipal supply, industrial networks, or cross-country pipelines — require more than just pipes. Ductile Iron (DI) fittings and valves play a decisive role in ensuring hydraulic integrity, long-term durability, and easy maintenance.

In tendering and procurement, fittings and valves are often under-specified, leading to project delays, cost overruns, or operational failures. Below is a comprehensive technical checklist that EPC contractors, consultants, and project owners should use when preparing or reviewing water transmission bids.


1️⃣ DI Fittings — Beyond Standard Connections

DI fittings are manufactured according to EN 545 / ISO 2531 standards and designed to withstand working pressures up to PN 25.

🔹 Bends & Elbows

  • Common angles: 11.25°, 22.5°, 45°, 90°

  • Application: Directional changes without compromising hydraulic performance

  • Key check: Internal lining (cement mortar, epoxy, or polyurethane) must be specified

🔹 Reducers

  • Concentric: Used in vertical sections to maintain hydraulic balance

  • Eccentric: Used in horizontal pipelines to avoid air pocket accumulation

  • Check compatibility with DI pipe nominal diameters (DN 80–1200 mm)

🔹 Tees & Crosses

  • Equal Tees: For branch connections of the same diameter

  • Reducing Tees: For branching into smaller lines

  • Ensure stress calculations comply with ISO 7186

🔹 Flanged Spigot Pieces & Dismantling Joints

  • Allow safe valve connections and provide tolerance for assembly/disassembly

  • Essential in pump stations and treatment plants

🔹 Caps & Plugs

  • For line terminations, hydrostatic testing, or future extensions

🔹 Couplings & Adaptors

  • Restrained and flexible types available

  • Allow joint deflection and vibration absorption


2️⃣ Valves — Control & Safety Components

Valves regulate flow, maintain pressure, and provide safety functions. In water transmission bids, the following must be considered:

🛑 Gate Valves

  • Range: DN 80–1000 mm

  • Pressure class: PN 10–25

  • Resilient seated preferred for water tightness; metal seated for high temperatures or abrasive fluids

💨 Air Release Valves

  • Dual or triple orifice

  • Critical for surge control and removal of entrapped air

  • Reduce risk of water hammer and energy losses

🚰 Butterfly Valves

  • Double or triple eccentric design (per EN 593)

  • Lightweight compared to gate valves for DN >1000 mm

  • Common in treatment plants and pumping stations

🔄 Check Valves (Non-Return)

  • Prevent backflow that could damage pumps or contaminate sources

  • Swing type or tilting disc for high DN

📏 Pressure Control Valves (PRVs, Surge Relief Valves)

  • Maintain downstream pressure at safe levels

  • Installed at high-pressure zones or district boundaries


3️⃣ Technical Considerations for Bids

  • Standards & Certification: EN 545 / ISO 2531 for fittings; EN 1074 for valves

  • Coatings & Linings:

    • Internal: Cement mortar lining (CML), epoxy, polyurethane

    • External: Bitumen, zinc + bitumen, epoxy, or 3LPE for aggressive soils

  • Hydrostatic Test Pressure (HTP): Usually 1.5 × PN

  • Gaskets & Bolting: EPDM/NBR gaskets, galvanized or stainless bolts

  • Installation Notes: Ensure access chambers for maintenance, especially at valve nodes


4️⃣ Pipekom’s Value in Water Transmission Projects 🌍

At Pipekom, we don’t just supply DI fittings and valves — we help clients design, specify, procure, and deliver complete pipeline packages.

🔧 Product Range

  • DI pipes, fittings, and valves (DN 80–1200 mm, PN 10–25)

  • Welded steel pipes (spiral & longitudinal up to DN 3000 mm)

  • Seamless & OCTG pipes for oil & gas

  • HDPE & GRP pipelines for sewage and storm water

📊 Engineering Support

  • Assistance with BoQ preparation and tender documentation

  • Guidance on coating selection (epoxy, polyurethane, FBE, 3LPE/3LPP)

  • Hydraulic calculations and valve sizing

🚚 Logistics & Delivery

  • CIF / CFR / DDP delivery to project sites in over 20 countries

  • Rapid mobilization — e.g., Jordan’s Madaba Project: 4 km of DN 600 DI pipes + valves delivered in 21 days

📝 Project References

  • Egypt: Mostakbal Masr — 11 km spiral welded DN 2000–3000 mm

  • Ghana: Seamless pipes for heavy oil transmission (6 km, 17 mm WT)

  • Libya: 7 km GRP for stormwater rehabilitation

 
 
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