PP Exhaust Duct Leak Test Plan: 7 Essential Controls

A PP exhaust duct leak test plan should define the tested duct sections, drawing revision, test method, safe test condition, inspection points, acceptance authority, repairs, and records before fabrication is released. It should verify the agreed ductwork assembly; it does not prove capture performance, chemical suitability, or system compliance by itself.

Before fabrication release, the plan converts approved assembly and test-boundary decisions into a handover record for the fabricated exhaust duct sections.

PP exhaust duct leak test plan: define the boundary first

The first decision is which assembly the plan covers. A complete duct run, a shop-fabricated section, a branch, a flange connection, and an inspection door do not present the same test boundary. Mark the boundary on the approved drawing and identify temporary closures, connections excluded from the test, and interfaces completed on site.

Use the PP exhaust duct leak test plan as the controlled project record for that identified assembly, rather than as a generic claim about the completed ventilation system.

OSHA describes an exhaust ventilation system as an assembly that can include a hood or enclosure, ductwork, collection equipment, an exhauster, and a discharge stack. That system view is why a duct-section test record must state its limits rather than imply that it proves the performance of the whole ventilation system. OSHA 1910.94 also distinguishes installation, inspection, maintenance, and operating checks.

Put the following items in the leak-test plan

• Document control: project name, drawing number, revision, duct-section tag, fabrication date, and responsible parties.
• Assembly definition: duct geometry, branch points, flanges, inspection doors, transitions, supports, and site interfaces within the test boundary.
• Material and joint traceability: approved PP sheet and welding-consumable references, plus the joint locations covered by the inspection.
• Project-approved test procedure: medium, sequence, temporary closures, instrumentation, hold period, safety controls, and the project acceptance criterion. Do not copy a pressure or duration from an unrelated duct system.
• Inspection record: visual observations, identified leakage points, repair reference, retest result, date, and acceptance signature.

Użyj PP ductwork RFQ checklist to establish dimensions, service conditions, access points, and delivery scope before the test plan is finalized. For welded joints, the PP welding-joint preparation guide helps define fabrication inputs that should be traceable in the inspection record.

Keep leak testing separate from system-performance testing

A leak-test plan starts only after the material, fabrication, and application factors for the PP duct have been documented. Those upstream decisions identify the assembly being reviewed; they do not convert a material test value into a duct leak-test criterion.

Local material-data reference for document control, not a duct acceptance limit:

A leak test is an assembly-quality check. It should not be represented as a fan-performance test, a capture-efficiency test, or confirmation that every chemical is suitable for the completed system. Those decisions depend on the installed system, airflow design, service medium, temperature, operating conditions, and applicable project requirements.

Where the ductwork carries corrosive fumes, confirm the actual chemical, concentration, temperature, and cleaning conditions with QEEHUA before final material selection. QEEHUA PP sheet is used for acid-and-alkali-resistant ventilation and environmental equipment applications, but project-specific suitability remains subject to confirmation.

The following QEEHUA production video provides general context for the cutting stage before a fabricated PP component is assembled and inspected.

Plan repairs and retesting in advance

QEEHUA’s internal product information separates PP sheet from PP welding rod because the sheet assembly and its joining consumable must be reviewed as related but distinct inputs. In a duct repair record, retain that distinction. Identify the affected duct section and drawing location first; then record the approved repair route, any consumable or process requirement supplied by the project, the inspection result, and the retest boundary. Do not reduce the record to PP repaired.

This detail is especially helpful when several duct sections look alike. It lets the handover package show which fabricated item was repaired, which controlled drawing governed the repair, and whether the same agreed test condition was reapplied. It does not make a performance claim about capture, chemical duty, or code compliance; it preserves the evidence needed for the project team to make those decisions.

The test plan should give the fabricator a clear route when an inspection point needs correction: identify the location, record the repair method, re-inspect the affected joint, and retain the final result with the same duct-section tag. A record that only says “passed” cannot show which drawing revision, boundary, or corrective action was accepted.

Handover package checklist

Release the duct section only after the project team can connect the accepted assembly to its final documents. The PP exhaust-duct handover guide provides the companion document set.

• Approved drawing and revision record.
• Duct-section identification and inspection locations.
• Test procedure and safety controls approved for the project.
• Inspection and retest records, including any repair references.
• Material and fabrication documents required by the purchase order.
• Open items, site interfaces, and responsibility for final system commissioning.

For a drawing review or an RFQ, kontakt QEEHUA with the duct layout, process medium, operating conditions, fabrication scope, and required acceptance records.

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