When used for the purchase of special purpose machinery a User Requirement Specification (URS) is a technical reference document specially prepared for purchase of capital equipment within the manufacturing sector. The specification is used to provide a list of requirements for new equipment and can also outline any associated commercial requirements within the scope of supply. The User Requirements Specification highlights the needs of the end user as well as any regulatory requirements that surround the particular environment or industry.
The URS document is passed on to the machinery supplier as a baseline for quoting against and can form the basis of a Functional Requirements Specification during the design stage.
A poorly written URS can result in miscommunication between the end user and the potential supplier/vendor, which in turn can lead to time wasted rewriting documentation or in a worst case scenario producing the equipment not suitable for the process.
Following are some simple Do’s and Don’ts:
Discuss the issues/requirements with all personnel involved. Who’s going to use the equipment? Who’s going to maintain the equipment? Who’s going to be responsible for the product? Each of person and department will have an interest in how the equipment is operated. Their needs should be included in the URS.
If validation of the equipment is required establish a validation plan NOW. The time to plan for validation is at the beginning when you’re writing the URS, rather than at the end when the equipment hits the floor. If you wait until installation, you’re putting the cart before the horse. This can lead to a compromised plan or the need to retest or revalidate equipment.
Include a good overview. This section should describe the machine and what it’s supposed to do. It should also include background information, such as similar machines, the processes currently being used and the working environment.
Include supporting documentation. If a standard or other specification are referred to such as a company electrical specification or contractors’ manual, it should be included as an attachment.
Don’t use time-based metrics. Today, performance metrics are almost always written as a time-dependent measurement. For example, “100 components/assemblies per minute.” This approach is too vague and does not take into account product yield and quality.
Don’t cover functional requirement specifications (FRS) in the URS. The overall intention of the URS is to describe what the equipment is supposed to do. How it performs is not a function of the URS.
Don’t place multiple requirements in a single section. This makes it hard to test and validate each independent requirement. Each requirement should be numbered and stand on its own.
Don’t duplicate requirements in multiple sections. You don’t want the same requirements repeated in five different sections of the document. This causes unnecessary work. Rather, collect the requirements in a general section and test them once.
Writing equipment specifications is a critical but often overlooked facet of every assembly project and manufacturing process. Equipment specifications are a prelude to issuing RFQs and, with appropriate revisions, become part of the actual purchase order for the equipment.