User Requirement Specification for Process Equipment: URS Template

A user requirement specification (URS) is the buyer's written statement of what a piece of equipment must do, set out as numbered, testable requirements before any supplier is asked to quote. In GMP manufacturing it is also the first qualification document: EU GMP Annex 15 says the equipment specification belongs in a URS, a functional specification or both, and the URS remains the benchmark for the whole validation life cycle [1, 2]. A good URS states what you need rather than how to build it, marks which lines are GMP critical, and says how each line will be checked.

Why this matters now

The URS is the yardstick at every later stage. Under Annex 15, its requirements are checked during design qualification (DQ), the documented check that the design is fit for purpose, and equipment is confirmed against it, where applicable at the vendor's site, before installation [1]. WHO guidance puts the URS at the start of qualification and expects the buyer to use it to choose the item from an approved supplier [2]. In the UK, licensed manufacturers must follow GMP, and the MHRA publishes the EU GMP guidance in its Orange Guide [9]. This is general information, not legal advice.

ASTM E2500, the guide to specifying, designing and verifying pharmaceutical manufacturing systems, was issued in a major revision on 15 March 2025 [3]. The 2025 edition separates product and process user requirements, which carry the critical quality attributes and critical process parameters, from general user requirements such as capacity, availability and environmental discharges [3].

Commercially, the URS is what you compare bids against. Approved internally before the tender goes out, it gives every supplier the same target and becomes the basis for holding the chosen supplier to account [7]. A vague URS produces quotes that cannot be compared and late change requests, yet ISPE's Q&A on commissioning and qualification says the factory acceptance test (FAT) and site acceptance test (SAT) are not the place to introduce changes [4]. Our guide to technical bid evaluation picks up from there.

URS, functional specification and design specification

WHO guidance on computerised systems even allows the URS and FS to be combined in one document [2]. For engineered equipment, keep them apart: the URS is yours, the FS is the supplier's answer, and the gap between them is what you evaluate. Our IQ, OQ and PQ guide covers later stages.

What stays out of the URS matters as much. ISPE's commissioning and qualification Q&A puts engineering specifications and standards, the means of meeting each requirement and contract terms outside it [4]. NHS guidance warns against requirements that limit the contractor's flexibility for no good reason [5]. Name the codes and regulations the equipment must meet without copying them in, and put price, delivery and payment terms in the RFQ (request for quotation).

For the control system, ISPE GAMP 5 (second edition, July 2022) covers computerised systems, and it encourages full use of supplier knowledge, experience and documentation [8].

How to write requirements suppliers can quote against

NASA's checklist for good requirements works for a vessel or skid too [6]:

• One requirement per line, uniquely numbered, so bids, tests and deviations can refer to it [6, 7].
• "Shall" for a requirement, "should" for a goal and "will" for a statement of fact [6].
• Describe the need and leave the solution open [6]. Leave the design to the supplier [7].
• Make it verifiable: a value, a tolerance and a method. Words such as adequate, easy, robust, sufficient and user friendly cannot be tested [6]. WHO's appendix on computerised systems asks for user requirements that can be tested or verified [2].
• Do not leave blanks. Where a value is unknown, give a best estimate marked "to be resolved", with an owner and a date [6].
• Prioritise every line [7], and classify it as below.

A GMP critical requirement traces back to a critical quality attribute (CQA), a product property that must stay within limits, a critical process parameter (CPP), a process setting that affects a CQA, or a design feature that affects cleaning or product quality [3, 7]. Business requirements cover capacity, availability, discharges, safety and site needs [3, 7]. Separately, mark each line mandatory or desirable. A bid that misses a mandatory line should be clarified or excluded, not scored on price.

Outside GMP, in chemicals or food, every line may be business, but the same rules apply.

A URS template, section by section

The layout below is our own, drawing on NHS and ISPE guidance [3, 4, 5]. Write one URS per item of equipment or system [5], and size it to the risk: a catalogue item may need only a data sheet and an order confirmation [7].

Add a traceability matrix as an appendix: each requirement number against the document or test that proves it [7]. After approval, changes to the URS go through version control [5], but it remains a living document, revised through change management whenever requirements change [4].

Practical example

An illustrative case: a buyer needs a 2,000 litre stainless steel vessel for a liquid product, heated through a jacket (an outer shell carrying steam or cooling water) and stirred by a top mounted agitator. The first draft said it "shall heat the batch quickly and be easy to clean". Neither phrase can be priced or tested. The rewritten lines follow; every figure is illustrative, and barg is bar above atmospheric.

For line 4.4, see our guide to EN 10204 3.1 and 3.2 certificates.

Line 4.2 also lets each bidder test feasibility. Taking water as about 1 kg per litre and 4.18 kJ/kg K, the batch needs 2,000 × 4.18 × 50 = 418,000 kJ, or 418 MJ. Over 90 minutes (5,400 seconds), that is an average duty of about 77 kW for the water alone, before vessel steel and losses: a figure a supplier can size the jacket against, where "quickly" was a guess.

Bidder A meets all six mandatory lines. Bidder B quotes a heat up time of 120 minutes, missing line 4.2, so its bid goes back for clarification before anyone compares prices. A draft line asking for delivery within 20 weeks of order was moved into the RFQ terms, because it is a contract term, not a user requirement [4].

Send one URS to every bidder

A URS only works if every supplier quotes against the same version. With ChemCapital, you send one structured RFQ to all your suppliers at once and compare their answers side by side. The audit trail logs every interaction, revision and decision with timestamps, which helps when a URS question resurfaces at DQ or FAT.

Ready to get bids you can compare line by line? Start a free 14 day ChemCapital trial, with no credit card needed.