Buyer's Guide

Valve Selection Guide

Written the way an experienced storekeeper would explain it across the counter — what each valve type is actually for, where people go wrong, and how to write a specification that gets you the right valve first time.

Step 1 — Isolation or control?

This single question eliminates most wrong answers. An isolation valve spends its life either fully open or fully shut; a control valve spends its life partly open. Valves designed for one are damaged by the other. Gate and ball valves isolate. Globe valves control. Butterfly valves can do both, which is part of why they are so popular.

Step 2 — Match the type to the duty

Valve type	Best for	Strengths	Watch out for
Gate valve	Isolation only	Full bore when open, near-zero pressure drop, handles solids and high temperature, economical in large sizes	Slow to operate, damaged by throttling, bulky and heavy above 200 mm
Ball valve	Isolation, quick shut-off	Quarter turn, bubble-tight seal, works on gas and liquid, easily actuated	Expensive above 150 mm, PTFE seats limit temperature, dead space can trap solids
Butterfly valve	Isolation and throttling	Very short face-to-face, light, cheap in large sizes, throttles acceptably 20–70% open	Disc always in the flow path, liner material must suit the medium, less tight than a ball valve
Globe valve	Throttling, regulation	Designed to run partly open, fine repeatable control, seats survive throttling	High pressure drop, more expensive, generally limited to 200 mm and below
Check valve (NRV)	Preventing reverse flow	Automatic, no operator needed; dual plate type minimises water hammer	Swing type slams on pump trip, all types need correct orientation
Plug valve	Isolation on dirty media	Handles tar, slurry and viscous fluids that jam ball valves	Higher operating torque, needs sealant maintenance on lubricated types

Step 3 — Body material

Cast iron — water and low-pressure service up to about 200°C. Cheapest per kilogram, brittle, do not use where impact or thermal shock is likely.
Bronze / gunmetal — potable water, small sizes, corrosion resistance without the cost of stainless. The default for building plumbing up to 50 mm.
Cast steel WCB — the general-purpose industrial choice for steam, oil and process service to Class 300.
Forged steel A105 — small bore, high pressure. Class 800 screwed and socket weld valves on steam and hydraulic lines.
Stainless 304 / 316 — corrosive media, hygiene, chlorides. Use 316 wherever chlorides are present; 304 elsewhere to save money.
Ductile iron — water networks and fire systems where cast iron's brittleness is a concern; the UL/FM listed choice for many fire products.

Step 4 — Pressure class and ends

Match the valve rating to the flange standard on the line, not to the operating pressure alone. A PN16 valve will not bolt to an ASA 300 flange. Common Indian combinations are Table E for water, ASA 150 for general industry, ASA 300 for higher pressure, and screwed or socket weld Class 800 for small-bore steam. Our flange tool will confirm what your existing flanges are.

Step 5 — Certification

Ask for it only if you need it, but do not discover you needed it after delivery.

ISI mark — required for most government, PWD, CPWD and municipal work, and for fire fighting products.
IBR Form III-C — legally required for valves and fittings on steam lines above the pressure thresholds in the Indian Boiler Regulations.
UL listed / FM approved — what fire NOC inspections and insurance surveys expect on hydrant and sprinkler mains.
API 6D / 600 / 602 — refinery, petrochemical and pipeline specifications.
NACE MR0175 — sour service with hydrogen sulphide present.
Third party inspection — Lloyd's, TUV, BV, SGS; adds cost and lead time, so flag it at enquiry stage.

Talk it through before you order

Describe the line — medium, size, pressure, temperature, what the valve is for — and we will tell you what to buy, including when a cheaper option is the right one.

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Valve selection — common questions

What is the single most common valve buying mistake?

Using a gate valve for throttling. A partly open gate vibrates in the flow, wire-draws the seating faces, and within months the valve will not shut off properly even when fully closed. If you need to regulate flow, buy a globe valve or a butterfly valve — the extra cost is trivial against replacing a damaged gate valve and draining the line to do it.

Is a more expensive brand always better?

No — it is better when the duty demands it. For steam, high pressure, IBR-governed service, sour gas or anything requiring third-party inspection and API certification, a premium brand like L&T or Audco earns its price in documentation and reliability. For a general water line in a building, a well-made ISI-grade valve from Sant, Zoloto or Kartar will do the same job for considerably less. Paying for certification you do not need is simply waste.

How do I specify a valve properly when asking for a quote?

Six things: type (gate/ball/butterfly/check/globe), size in mm or inches, pressure class or rating (PN16, Class 150, Class 800), body material (CI, CS WCB, SS 316, bronze, forged A105), end connection (flanged Table E or ASA, screwed, socket weld, wafer), and any certification needed (ISI, IBR, UL/FM). Give us those and the quotation will be right first time.

Need a price today?

Send us your BOQ, drawing or item list on WhatsApp and get a written quotation the same working day. Ready stock for most sizes at our Delhi godown.

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