Surface preparation for intumescent: verify the primer and required condition
A university laboratory's columns arrive with visible weld spatter and an incompletely identified primer. The coating crew needs a reviewed preparation route before its first application.
Identify the substrate and primer, then verify the preparation and condition required by the selected coating system. A manufacturer's public application manual requires an accepted primer and properly prepared, clean surfaces; it also calls for technical advice where the existing primer is unknown. That example establishes the need to check the actual route, not a universal surface profile, cleaning recipe or primer approval test.
Put the requirement into the work record
- Collect the incoming steel evidence. Record the member identifiers, fabricator's coating information and delivery condition. Ask for the actual primer name, application record and relevant documents. 'Shop primed' is a description of a stage, not identification of the material beneath the proposed intumescent coating.
- Trace the preparation requirements. Assemble the current project specification, applicable design and coating and primer instructions. Ask the qualified contractor to identify the required substrate condition and supporting inspection records. Keep requirements for different substrates separate rather than applying a carbon-steel assumption to every coated surface.
- Resolve an unknown or unlisted primer. Send the available product and condition evidence for the required technical review before coating that scope. Obtain a documented response and complete the project's approval process. A favourable site observation or an isolated adhesion result should not be presented as blanket approval for the system.
- Agree corrective preparation before it begins. Record the directed method, extent, responsible qualified crew and required checks. Coordinate access and the site's safety arrangements. Do not instruct a crew to grind, blast or solvent-wipe from a generic checklist; those choices need the actual material and procedure requirements.
- Verify readiness at the identified locations. Ask the responsible personnel to record the completed preparation and required findings against members or defined areas. Note unresolved spatter, contamination or coating questions factually. Keep the affected scope distinguishable from neighbouring members that have completed the prescribed checks.
- Protect the prepared scope until application. Name who will notify the coating contractor about later welding, handling or contamination. Recheck the affected condition through the actual procedure before resuming. Link any new preparation or primer work to the original record so the first coat does not hide an unresolved change.
Common mistakes
- Treating 'shop primed' as a named approved primer.
- Covering unresolved preparation to preserve the spray date.
- Using a test result as automatic system approval.
Checklist
Keep the preparation route traceable
- Members and substrate identified.
- Primer named and evidence collected.
- Current preparation references available.
- Unknown coatings resolved through review.
- Directed work and checks recorded.
- Later changes notified before application.
Check your understanding
Can the crew proceed because the primer looks sound and another job used the same colour?
Show the answer
No. Identify the primer and verify the required preparation and system route. Colour and visual condition do not resolve an unknown coating or replace the documented review.
