Listed system or engineering judgement: when each is the right answer
A conduit group passes through a sloping parkade slab. The submitted system assumes a different opening arrangement. The foreman can make the seal look tidy, but cannot show that the actual construction matches the listed detail. The installation question needs a documented technical decision.
Use a matching tested system where available. If the actual condition has no suitable match, document the difference and ask the responsible technical team about a supported engineering judgement and its acceptance route. The cited application guide distinguishes tested systems from judgements based on relevant test evidence. An engineering judgement is not a newly tested listing or a routine way to bless work that was installed differently.
Send a question the technical reviewer can assess
- Check the proposed match completely. Compare assembly construction, opening, services and other stated parameters with the actual condition. Have the responsible installation and design team confirm the mismatch. Do not reject a suitable listing merely because another approach uses a material already on the truck.
- Consider a supported design adjustment. Ask whether the opening or service arrangement can be revised through the proper process to match an available system. Review access, structure and other affected requirements with their owners. Moving or enlarging a service opening is not a foreman’s informal shortcut.
- Prepare the specific field evidence. Provide current drawings, location, assembly information, service materials and sizes, measured opening geometry and clear photographs from safe access. Label unknowns. A sketch showing only the desired sealant colour gives the reviewer too little to evaluate.
- Identify the judgement’s basis and author. Request the documented technical assessment from an appropriately competent issuer with relevant system and test information. Record which products and conditions it addresses. Do not assume any letter carrying an engineer’s name establishes that every affected requirement has been assessed.
- Obtain the actual required acceptance. Confirm the project professional, authority and contract review route applicable to the solution. Record its conditions and installation status before relying on it. A received proposal, a supplier email and an accepted solution are different states.
- Control installation and later changes. Give the accepted detail to the responsible crew with its exact location and conditions. Retain required inspections and closeout records. If the opening or services change again, refer the difference rather than extending a location-specific judgement by copying its reference to every nearby hole.
Common mistakes
- Calling an engineering judgement a tested listing.
- Requesting a letter without measured field conditions.
- Extending one accepted judgement to different openings.
Checklist
Before relying on a judgement
- Complete tested-system comparison.
- Defined unmatched condition.
- Checked alternative design options.
- Measured evidence and documented technical basis.
- Actual required acceptance and conditions.
- Controlled installation and change record.
Check your understanding
The supplier has emailed a proposed judgement. Is that the same as permission to install?
