New Instrument Selection & Specification SOP

How it works

1. Replace the lanes with your actual roles

   This chart uses Sales / Account Management, Instrumentation Engineering, Compliance / QA and Procurement. If your team splits proposal-writing from customer approval tracking, or a separate compliance officer signs off instead of QA, give that role its own lane rather than folding it into an existing one — the handoff is usually where a step gets assumed done by someone who assumed someone else did it.

2. Put your own reasoning into the selection step

   "Select measurement principle" only works as a real judgment call if the comment field carries the actual reasoning, not just the chosen technology. Write the medium, constraints and why one principle beat the alternatives into the row so the choice can be checked later, not just trusted.

3. Name what counts as a compliance gap

   "Compliance requirements met?" is only useful if compliance and engineering agree in advance on what routes to the No branch — a missing material certificate, a hygienic-fitting mismatch, a hazardous-area marking that needs the ATEX SOP instead. List examples directly in "Resolve compliance gap or select alternate instrument" so the check isn't interpreted differently by whoever is on duty.

4. Set People and Workload on every row before you rely on the BI panel

   The workload panel can only total hours for rows that carry them. Fill in People and Workload for each step as you adapt the chart, using realistic effort hours rather than elapsed time, so a busy specification week actually shows up as a busy week for the right engineer.

5. Decide who has authority to approve on the customer's behalf

   "Customer technical approval?" assumes the customer's own technical contact reviews the proposal. Name that contact's role in your version of the chart so Sales isn't guessing whether a verbal yes from the wrong person is enough to move to quotation.

Frequently asked questions

What triggers the start of the instrument selection process?

The process starts at "Customer requirement received": a tag number, service description and, where relevant, the instrument being replaced. Everything downstream, the medium and constraints gathered, the principle selected, the compliance check run, keys off this record.

Why does selecting a measurement principle come after assessing constraints instead of before?

"Select measurement principle" follows "Understand medium and process conditions", "Define measurement requirements" and "Assess pressure, temperature, flow and environment constraints" deliberately: the same nominal duty can call for a different technology once the actual conditions are compared, so the principle is chosen from the gathered facts rather than assumed at intake.

What happens if compliance requirements aren't met?

The "Compliance requirements met?" decision routes a gap to "Resolve compliance gap or select alternate instrument" before a proposal ever reaches the customer, then loops back to re-check rather than letting the gap ride forward into a quotation. Hazardous-area certification is handled under the separate ATEX Instrument Selection & Installation SOP, not this step.

Who decides whether the proposed instrument is approved?

That's the "Customer technical approval?" decision, and in this chart it sits with the account manager tracking the customer relationship. Changes requested route to "Revise instrument selection with customer feedback", which loops back to a re-proposal rather than starting the whole selection process over.

Does this SOP cover ordering and installing the instrument too?

No — it ends at "Quotation accepted, order confirmed". Once an instrument is ordered, the Process Instrument Installation & Commissioning SOP picks up from there: reviewing the specification, verifying the equipment on site, and taking it through loop testing and commissioning.