DOP Testing & Equipment Servicing

Ensuring HEPA Integrity and Site Safety Across New Zealand.

In the asbestos removal industry, your equipment is your primary line of defense. Passive Safety Group, in partnership with the specialist team at Smooth Flow, provides comprehensive, on-site servicing and DOP (Dispersed Oil Particulate) testing to ensure your fleet remains compliant with the Health and Safety at Work (Asbestos) Regulations 2016.

Don't risk site shutdowns or HEPA failure. Get your NPUs, H-Class Vacuums, and Decon Units certified by the experts.

Negative Pressure Units

Professional Negative Pressure Units for asbestos removal enclosures. Suitable for friable work requiring compliant airflow and enclosure pressure control.


We provide full servicing and certified DOP testing for the following brands

  • SMH
  • AMS
  • Beacon
  • BEST

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Professional Asbestos Vacuums (H-Class)

High-performance hazardous dust extraction units designed for asbestos removal and remediation. These H-Class vacuums ensure the safe collection of toxic fibers while maintaining a clean, compliant work environment. Available in Small (Dry-only), Medium (Wet/Dry), and Large (Industrial/Continuous) models.

We provide full servicing and certified DOP testing for the following H-Class brands

  • Nilfisk VHS 42 / Attix
  • Kerstar
  • Numatic
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3-Stage Modular Decontamination Units (DCU)

A portable, high-integrity hygiene system for sites with restricted access. Provides a compliant 3-stage transition (Dirty-Shower-Clean) to ensure total containment and personnel safety.

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Water Management Systems (WMS)

High-efficiency filtration units that remove asbestos fibers from shower waste. Ensures all wastewater is treated and compliant before discharge.
We provide full servicing for the following brands

  • SMH
  • AMS
  • Beacon

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Omniguard Pressure Recorders

Precision differential pressure monitors for asbestos enclosures. Provides real-time alerts and documented proof of containment to ensure site safety and compliance.

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