• Fire-Resistant Duct Inspection Services

  • Shanghai OKRO Construction Technology Co., Ltd. provides professional on-site inspection services for fire-resistant ductwork, ensuring building ventilation, grease, and hazardous exhaust systems maintain their fire-resistance integrity under fire conditions, effectively preventing the spread of smoke and flame to maximize occupant and property protection. Services are conducted in accordance with ISO/IEC 17020 and recognized under IAS AC98 accreditation, with all inspectors authorized under international standards.

  • Reference Standards

    • ASTM E3385: Standard Practice for On-site Inspection of Fire Resistive Duct Systems
    • UL 2221: Standard for Tests of Fire Resistive Grease Duct Enclosure Assemblies
    • ASTM E2336: Test Methods for Fire Resistive Grease Duct Enclosure Systems
    • ASTM E2816: Test Methods for Fire Resistive Metallic HVAC Duct Systems
    • ISO 6944-1: Fire Containment – Ventilation Ducts
    • GB 50243-2016: Code of Acceptance for Construction Quality of Ventilation and Air Conditioning Works
    • GB 51251-2017: Technical Standard for Smoke Management Systems in Buildings
      GB/T 17428-2009: Fire-Resistance Test Methods ofVentilation Ducts

    Scope of Inspection

    • Grease Duct Systems: Assess compliance of commercial kitchen exhaust duct systems with fire-protection requirements
    • HVAC Duct Systems: Verify metallic duct construction, fire compartmentation, and installation quality
    • Hazardous Exhaust Systems: Inspect ventilation ducts in chemical, laboratory, and other high-risk industrial settings

  • Inspection Process

    1

    Preparation Stage

    • Review inspection documents, construction drawings, listing certificates, and test reports
    • Verify materials (model, thickness, fireproof coating, reinforcements, manufacturer, certification)
    • Prepare calibrated measurement tools (coating thickness gauge, calipers, steel tape, etc.)
    • Develop the on-site inspection plan includingsafety measures​
    2

    Site Inspection

    Key Focus Areas

    • Duct Construction: Material, specification, seam type, airflow ratings as per listing
    • Joints & Connections: Flange types, spacing, assembly methods
    • Reinforcements: Rod size, interval, correct installation
    • Fire Protection System: Rated performance hours, coating thickness, material density, joint sealing
    • Supports & Hangers: Type, size, and interval, per listing and codes
    • Access Doors (if applicable): Structure andfire-protection methods​
    3

    Reporting and

    Re-Inspection

    • Non-conformities and results recorded using a dedicated checklist and marked onsite
    • Detailed inspection report issued outlining deficiencies and required corrective measures
    • Upon rectification, follow-up inspectionconducted; records and acceptance documentation updated accordingly
    4

    Deliverables

    • Work Instruction for Fire-Resistant Duct Inspection
    • Inspection Checklist
    • Inspection Report​

  • Key Advantages

    • Full compliance with both national (GB) and international standards with certified authority
    • Traceable inspection process: documentation, images, and reports integrated and archived
    • Systematic risk mitigation support for owners, contractors, and insurers, facilitating prompt identification and remediation of potential hazards
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