How to Specify Pipes & Fittings for Industrial Piping Systems

Specifying pipes and fittings incorrectly is one of the most common and costly mistakes in industrial procurement. A mismatch in pressure rating, material, or connection type can mean a failed installation, a safety risk, or a part that simply does not fit -- after lead times have already been spent. A clear specification process avoids all three. ## Step 1: Confirm the Media Being Carried The substance flowing through the pipe -- water, steam, oil, gas, or corrosive chemicals -- determines which materials are even viable candidates. Carbon steel is a common default for general industrial service, but it is unsuitable for many corrosive chemical lines, where stainless steel, PVC, or specialised alloy piping is required instead. Getting this step wrong early invalidates every other spec decision that follows. ## Step 2: Determine Pressure and Temperature Ratings Every pipe and fitting has a pressure-temperature rating that must exceed the maximum operating conditions of the system, not just its average conditions. This is usually expressed against a schedule (e.g. Schedule 40, Schedule 80) for pipe wall thickness, and a pressure class (e.g. Class 150, Class 300) for flanges and fittings. Under-specifying here is a genuine safety hazard, not just a performance shortfall. ## Step 3: Choose the Connection Type - **Threaded** connections suit smaller-diameter, lower-pressure lines and allow easier disassembly for maintenance - **Flanged** connections are standard for larger-diameter or higher-pressure industrial systems, and allow full bore access for inspection - **Welded** connections offer the most reliable seal for high-pressure or hazardous media but require certified welding and are harder to modify later - **Compression and push-fit** fittings are common in lower-pressure utility and instrumentation lines where frequent reconfiguration is expected ## Step 4: Confirm Standards Compliance Industrial piping is typically specified against recognised standards such as ASME B31.3 for process piping, or equivalent national and international standards depending on the destination country and industry. Confirming which standard applies to a given installation avoids sourcing parts that are dimensionally or materially incompatible with the rest of the system. ## Step 5: Account for Fittings, Not Just Pipe Elbows, tees, reducers, unions, and valves all need to match the pipe's material, pressure rating, and connection type. A mismatched fitting -- for example, a lower-pressure-rated elbow installed on a higher-rated pipe run -- becomes the weakest point in the entire system, regardless of how well the pipe itself is specified. ## Sourcing Pipes and Fittings Once material, pressure rating, connection type, and standard are confirmed, sourcing is a matter of matching that specification to a real manufacturer part number or equivalent. CrestLink Engineering supplies pipes and fittings against exact specification, worldwide, with quotations built around confirmed part numbers, quantities, and delivery requirements. For projects where the exact part number is not yet known, submitting the media type, pressure rating, and connection type in a quote request allows CrestLink's team to confirm a suitable specification before quoting.