Maintenance – User Requirements Specification

URS – User Requirements Specification, or User Requirements Specification, is the cornerstone of any project in the pharmaceutical industry carried out in accordance with Good Manufacturing Practice (GMP) principles. A URS is a formal document in which the end user defines, in detail, their requirements and expectations for a new system, piece of equipment, or process. In the pharmaceutical sector—one of the most stringent and highly regulated— a properly prepared URS ensures that the designed installation or machine will meet all quality, safety, and regulatory compliance criteria. In other words, the URS translates business and operational needs into specific technical requirements that must be delivered during the project.

URS – User Requirements Specification – what is it?

URS – User Requirements Specification defines the key requirements for a new system in line with GMP.

URS – User Requirements Specification is a structured document describing all essential needs and functionalities that the end user expects from the planned system or equipment. Put simply, a URS is a set of requirements necessary to create a solution that fully meets the system’s intended purpose and use. This document covers the requirements of the owner and future operators, as well as the engineering constraints of the project, so that clear success criteria are established from the outset.

In pharmaceutical manufacturing, the URS is of particular importance because it serves as the starting point for design and, subsequently, for system qualification and validation. In line with the EU GMP Annex 15 guidelines (qualification and validation), the specification for new equipment or a system should be defined in the URS, and all requirements included in it must be verified during Design Qualification (DQ). This means that no material user expectation can be overlooked—throughout the equipment lifecycle, the URS is the reference point that ensures the final solution truly meets the requirements of both the customer and regulators. Engineers and quality specialists often stress that the URS is the foundation of a machine or system project: it is used to plan acceptance testing and the entire validation effort to confirm that the assumptions and GMP requirements have been met.

URS content

A good URS should be comprehensive, unambiguous, and verifiable. This means that every stated requirement can later be checked (e.g., during FAT/SAT testing or IQ/OQ/PQ qualification). The scope of a User Requirements Specification may vary depending on the type of project (production line, a single machine, an IT system, etc.), but it typically covers the following areas:

• Functional requirements – A detailed description of the functions and operations the system must perform. At this stage, the user describes what the system is expected to do (e.g., types of process operations, action sequences, operating modes). For example, for an ampoule filling machine, a functional requirement would be the ability to automatically dispense a specified liquid volume into containers with the required accuracy.
• Performance requirements – Defining the expected throughput and efficiency. The user specifies, among other things, the target production rate (e.g., how many units per hour), allowable cycle times, quality indicators (yield), and operational availability. Performance requirements should be measurable—for example, throughput of at least 5000 tablets per hour with 98% line availability. This makes it possible to verify whether the finished system meets these criteria.
• Safety and quality requirements – All aspects related to product and operator safety. In pharmaceuticals, key requirements include cleanliness and sterility (e.g., cleanroom class A, B, C, or D in accordance with GMP), the use of materials approved for contact with the medicinal product (e.g., 316L stainless steel, FDA-compliant seals), and measures to prevent cross-contamination. In addition, the URS must address workplace safety—for example, required guards, interlocks, and other elements compliant with machine safety regulations. All of these guidelines ensure the solution is safe and compliant with Hygienic Design principles and quality standards.
• Regulatory requirements (legal compliance) – In the pharmaceutical industry, meeting legal and standards requirements is critically important. The URS should therefore include references to the applicable regulations the system must comply with. These include, above all, GMP principles, as well as, for example, the Machinery Directive 2006/42/EC (machine safety requirements) and its successor, Regulation (EU) 2023/1230. If the project involves a control system, it is worth including requirements for compliance with FDA 21 CFR Part 11 (for electronic systems) or the GAMP5 guidelines. All of these regulatory requirements must be clearly specified so that designers and suppliers take them into account from the very start of the project.

In addition to the above, the User Requirements Specification often includes other sections such as: environmental requirements (e.g., the operating temperature and humidity range for equipment, if relevant), integration requirements (e.g., the need to interface with existing SCADA systems or Manufacturing Execution Systems, communication protocols, user interfaces), service and maintenance requirements (e.g., expected reliability, ease of cleaning and maintenance, access to spare parts), and training and documentation (which operating instructions, procedures, and training must be delivered with the system). It is important that all requirements are written in an active, unambiguous way, avoiding the passive voice—so there is no room for interpretation by suppliers or by auditors verifying the equipment’s compliance with the URS.

How to prepare a URS?

Preparing a User Requirements Specification should be a structured, collaborative process. Although the user (e.g., a pharmaceutical company) is responsible for defining the URS, in practice specialists from different departments are involved, and often technology suppliers also participate as advisors. Here are the key steps in developing a URS:

1. Identifying user needs – First, gather information from all future users and stakeholders about their needs, expectations, and constraints. This means talking to production operators, process engineers, the quality department, maintenance, and even procurement or safety. The goal is to understand what the system is expected to achieve and which problems it should solve. At this stage, it’s best not to filter ideas—capture all requirements, and do any selection or refinement in the next step.
2. Stakeholder analysis and consultations – Based on the collected input, create an initial list of requirements. Next, it’s worth reviewing it together with all key stakeholders. The quality department may point out additional regulatory requirements that production did not consider (e.g., the need to perform IQ/OQ/PQ qualification or validate cleaning methods), while the maintenance department may highlight servicing, maintenance, or calibration considerations. Cross-functional consultations help ensure that no important aspect is overlooked and that the requirements do not conflict with one another.
3. Drafting the URS document – With an agreed list of needs, the next step is to write the actual document. Requirements should be organized into logical categories (as described in the previous section) and assigned unique identifiers or numbers. Requirements should be written in an active, unambiguous form. For example, instead of the passive: “Temperature should be controlled”, it is better to write: “The system controls the process temperature within the range of 2–8°C with an accuracy of ±0.5°C”. This wording is clear and verifiable. It is also important to avoid prescribing specific solutions in the requirements—URS should state what must be done, not how. Leaving flexibility in the how (i.e., on the supplier and designers’ side) makes it possible to find the optimal technical solution. If the user dictates, for example, a specific device model or technology upfront, they may unintentionally limit the opportunity for a better solution.
4. URS review and approval – The completed document should undergo a formal review. Ideally, it should be carried out by representatives of all departments previously involved in defining the requirements, as well as decision-makers (project leadership, compliance/regulatory, etc.). The purpose of the review is to identify any gaps, ambiguities, or incorrect assumptions. After updates are made, the next step is formal URS approval—sign-off by authorized individuals (e.g., the engineering manager and the quality manager). From that point on, the URS becomes the working baseline for designers and suppliers. It is crucial that any later changes to the URS (if they become necessary) follow a formal change control procedure—each change should be assessed for its impact on the project and approved, to maintain consistency across the entire validation process.

URS and validation and GMP compliance

The User Requirements Specification does not stop being relevant once equipment design begins—on the contrary, it stays with the project through acceptance and final qualification. In the pharmaceutical industry, every system must undergo a formal qualification and validation process to confirm that it operates as intended and in line with GMP requirements. The URS is the backbone of that process.

As early as the Design Qualification (DQ) stage, the final design (drawings, technical specifications) is checked to confirm it meets all requirements defined in the URS. If any URS item is not addressed in the design, this is the moment to catch the nonconformance and implement corrections before the machine is built. Then, once the equipment is built, it goes through IQ, OQ, PQ qualification (Installation/Operational/Performance Qualification – Installation, Operational, and Performance Qualification). Each of these stages ties back to the URS: during IQ, we verify, among other things, that all components have been installed in accordance with the URS requirements; during OQ, we test the functions and alarms described in the URS; and during PQ, we confirm that the system’s throughput and quality of operation meet the criteria defined in the URS. In other words, the URS is treated as a checklist of critical requirements that must be formally confirmed during qualification.

Acceptance testing at the supplier’s site and at the installation site is also based on the URS. In the pharmaceutical industry, it is standard practice to carry out a Factory Acceptance Test (FAT) at the machine manufacturer’s facility and a Site Acceptance Test (SAT) after the system has been installed at the plant. Both stages involve comprehensive testing of the equipment against a previously agreed protocol—and that protocol is developed specifically from the URS requirements. For example, if the URS requires the system to generate automatic process reports, then FAT/SAT will include a test point confirming that those reports are present and correct. Best practice (set out, among others, in the referenced EU GMP Annex 15) is to demonstrate already at the FAT/SAT stage that the system meets all key user expectations before formal qualification begins under production conditions. This helps avoid surprises during audits and certification—the FAT/SAT test documentation provides evidence that the equipment was delivered in line with the requirements.

It is worth emphasising that full compliance with the URS is not only an internal project matter, but also a regulatory expectation. During audits, auditors very often check whether there is a documented cause-and-effect chain from the URS through to the validation results. If a given quality criterion is not captured in the URS, it is difficult to expect it to later become part of qualification testing. That is why, when drafting a URS, you need to think ahead: how will we verify each requirement? who will confirm it? can it be measured or audited? This approach, often referred to as “validation by design”, ensures that later qualification stages are already taken into account during the design phase.

URS – User Requirements Specification is one of the most important documents in projects delivered in accordance with GMP. It acts as a contract between the user and the technology supplier—it defines what is to be delivered and which criteria must be met for the solution to be accepted. In the demanding pharmaceutical sector, a well-written URS ensures a shared understanding of the project objective, minimises the risk of errors or misaligned expectations, and provides the foundation for validation of the entire system. When preparing a URS, all stakeholders should be involved; requirements should be specific and unambiguous, while still leaving room for optimal technical solutions. Only then will the final outcome—whether a new production line, a reactor, a SCADA system, or another investment—be not only compliant with regulations and GMP requirements, but above all will fulfil its business purpose by delivering a safe and effective final product. Everything starts with well-defined requirements—meaning a robust URS.