P&ID Creation and Updating

A piping and instrumentation diagram (P&ID) is the primary reference document for a compressed air, nitrogen or process water system. It shows every piece of equipment, every instrument, every valve and every connection in the system, using standardised symbols, in accordance with ISO 10628 (flow diagrams for process plants) and BS 1553-1 (British Standard for piping and instrument symbols). Without an accurate P&ID, engineers cannot safely isolate sections of the system, modifications cannot be properly planned, and compliance with PSSR 2000 is harder to demonstrate.

ALS Industrial Services Ltd carry out P&ID surveys for compressed air, nitrogen generation and process water chiller systems. We survey the physical installation, document it fully, and produce a written record that reflects the system as it actually exists.

New P&IDs

Where no P&ID exists, our engineers survey the full installation, walking the pipework, recording every item of equipment, instrument, valve and safety device, noting pipe sizes, materials, flow directions and operating pressures. The result is a complete and accurate record of the system as installed, including all tag references for instruments and equipment.

Many sites operate systems that were never formally drawn up at installation, or where original drawings were lost or were never completed. A survey-based P&ID creates a reliable baseline for maintenance, modification and compliance work going forward.

Updating existing P&IDs

P&IDs go out of date when plant is modified, extended or partly decommissioned without the drawings being revised. This is common on sites that have grown piecemeal over a number of years. Our engineers review the current drawing against the actual installation, identify every discrepancy, and produce a revised document with a full revision record showing what has changed and when.

Common situations requiring a P&ID update include:

• New compressor, dryer, receiver or filter added to an existing system
• Ring main extended to serve a new production area
• Nitrogen generator installed and connected to existing pipework
• Process water chiller circuit modified or expanded
• Safety valve, pressure gauge or instrumentation replaced with a different specification

Why an accurate P&ID matters

An accurate P&ID is a practical requirement for safe maintenance and modification of a pressure system. It defines the system boundaries that a Written Scheme of Examination (PSSR 2000) relies on. It enables engineers to identify isolation points before working on live sections. It supports any HAZOP or risk assessment carried out on the system. And it provides the documentation that HSE inspectors, insurers and auditors expect to see.

Operating a significant compressed air or nitrogen system without accurate documentation is a common finding in HSE and insurance audits, and is one of the simpler risks to address.

How can we help?

Our engineers understand compressed air, nitrogen and process water chiller systems in detail, which means a P&ID survey produces an accurate and complete document rather than a generic record. Whether you need a drawing produced from scratch or an existing one brought up to date, we can carry out the survey and provide the documentation you need.

Call us on 01789 867640 or email enquiries@alsindustrial.co.uk. We respond to all enquiries the same working day.