Before the Nozzle Opens: A Facilities Manager's 12-Stage Pre-Blast Audit
Photo: facilities manager pre-blast site inspection containment industrial stock photo, via unblast.com
A pre-blast walkround is not a courtesy. It is the last point at which a live site can be stopped cheaply. Once containment is up, services are isolated and the nozzle opens, every missed check becomes a variation, a delay or a defect. For facilities managers in 2026, the audit is as much a client control as a contractor obligation.
Why the walkround belongs to the client as well as the contractor
Blasting exposes latent defects: moisture, salts, incompatible coatings and hidden services. The contractor controls the method, but the facilities manager controls access, building history and operational constraints. A joint audit creates a record of what was known before work began. It also gives both parties a clear hold point: no signature, no start.
The 12-stage pre-blast audit
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Confirm scope and substrate history. Record the substrate, previous coating systems, repair history and any areas of unknown provenance. A 1970s steel frame and a modern galvanised section do not behave in the same way.
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Check moisture and dew point. Blasting and coating must not proceed when the substrate is wet or when the dew point margin is too close. Record readings at several locations, not just at the access point.
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Test for salt contamination. Soluble salts can survive blasting and sit beneath a new coating. Use a recognised test method and record the results against the specification. This is the check most often skipped when the programme is tight.
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Assess existing coating compatibility. Identify the existing coating type where possible. A new system that is incompatible with the old primer can fail at the interface even if the surface profile is correct.
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Screen for asbestos and hazardous coatings. Confirm the asbestos survey status and identify lead, chromate or other hazardous coatings before disturbance. The waste route and containment design depend on this finding.
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Agree containment and ventilation. Confirm the enclosure, negative pressure, filtration and monitoring arrangements. On a live site, dust escape is both a health issue and a reputational one.
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Isolate services and protect sensitive equipment. Lock off electrical supplies, isolate fire detection where permitted, and protect sprinklers, sensors and nearby finishes. Record the isolation and reinstatement procedure.
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Confirm access and egress. Check scaffold ties, edge protection, lighting, rescue arrangements and the route from the blast area to the waste compound. A good method statement fails if people cannot move safely.
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Set the waste route and classification. Agree where spent media and coating residue will be stored, how it will be tested and who will sign the duty of care paperwork. Do not leave waste routing until the first skip is full.
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Complete permit and sign-off controls. Confirm the permit to work, hot works arrangements where relevant, and the named sign-off for each hold point. The audit should produce a signed checklist, not a verbal understanding.
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Run a trial patch and agree acceptance criteria. A trial is not a full production run. It confirms the media, pressure, profile and coating compatibility before the programme is committed.
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Confirm emergency and environmental response. Check spill kits, fire response, first aid, drainage protection and the contact route for site emergencies. The plan should be tested before the first blast, not after an incident.
Case example: the missed chloride check
At a distribution centre in the Midlands, a contractor was asked to prepare steel roof beams before recoating. The walkround covered access, containment and service isolation, but no one tested for soluble salts. The existing coating was removed, the steel was blasted and the new coating was applied. Within four months, blistering appeared along the top flange. Investigation found chloride contamination from a previous cleaning regime. The coating system had to be stripped back, re-blasted, re-tested and reapplied. The final bill exceeded £10,000 once access, containment and lost use of the bay were counted. The missed check was not exotic; it was a salt test that would have added less than an hour to the programme.
Making the audit stick
A checklist only works if it has consequences. The facilities manager and the contractor should sign the same document, photograph the completed containment and record the readings. Any change to scope, coating or access should trigger a review of the relevant points. FlowTech Blasting's view is that the pre-blast audit should be treated as a formal handover: clear evidence, clear ownership and a clear go or no-go decision. That discipline is cheaper than discovering the problem under a new coating.
