Every validation engineer has seen it. The project is behind, the supplier has sent a forty-page technical specification, and someone reformats it into the site URS template. The section headings change, the wording softens, "shall" replaces "is", and the document is issued. It reads well. It is internally consistent. It is also worthless as qualification evidence.
Design Qualification asks one question
Design Qualification is the documented verification that the proposed design of the facilities, systems and equipment is suitable for the intended purpose. The word doing the work is proposed. DQ compares two things: what the user needs, and what the supplier proposes to build. If both documents originate from the supplier, the comparison is circular. You are checking the design against itself.
An auditor does not need to be a subject-matter expert to spot this. Two questions expose it:
- Which document came first, the URS or the supplier proposal?
- Which requirements in the URS would this supplier have failed?
If the answer to the second question is "none", the URS did not specify anything. It described.
What gets lost
A supplier specification is a description of a product that exists. A URS is a statement of what the process needs. The gap between them is where every meaningful requirement lives.
| Written from the vendor specification | Written from the process |
|---|---|
| "Filling accuracy ±1% of target volume" | "Fill weight shall remain within ±2% of label claim across the full batch, verified at a sampling frequency that supports parametric release" |
| "Machine constructed of 316L stainless steel" | "All product contact surfaces shall be 316L with Ra ≤ 0.8 µm, documented by material certificates traceable to component level" |
| "CIP connection provided" | "The product path shall be cleanable in place to a residue limit derived from the site's cleaning validation, with drainability demonstrated at the installed slope" |
| "PLC with recipe management" | "Recipe parameters classified as critical shall be modifiable only by an authorised role, with each change recorded in an audit trail retrievable for the life of the record" |
The left column can be met by exactly one machine. The right column can be met by several, and can be failed by some. That is the difference between a specification and a description.
The acceptance criteria problem
Requirements written from a supplier document tend to inherit the supplier's units and tolerances. That feels precise, but it silently transfers the burden of proof. If the URS says "±1% of target volume" because the brochure said so, the qualification protocol will test ±1%, the machine will pass, and nobody will have asked whether ±1% is adequate for the product. The tolerance that matters is the one derived from the label claim, the pharmacopoeial uniformity requirement and the site's own process capability.
The same happens with speed, changeover time, environmental classification, alarm handling and data retention. Each becomes whatever the supplier already achieves.
What a defensible sequence looks like
The URS is issued before the enquiry goes out. The supplier responds against it. The response is assessed requirement by requirement, and the assessment records three outcomes only: met, met with a deviation the user accepts in writing, or not met. That record is the Design Qualification. It takes an afternoon when the URS came first and is impossible when it did not.
If the equipment is already selected
This happens, and it is not automatically a finding. Where a machine has been chosen commercially before the URS exists, the honest route is to write the URS from the process, then run the comparison knowing that some requirements will come back "not met". Those become documented deviations with a risk assessment and, where needed, procedural controls. A URS with five accepted deviations is a stronger document than one with none, because it shows somebody looked.
The practical test
Before issuing a URS, take any ten requirements at random and ask, for each: could a competent supplier read this and quote a machine that fails it? If the answer is no for most of them, the document is a description of a purchase, not a specification of a need — and DQ against it will demonstrate nothing.