Having spent over 20 years managing asbestos removal jobs, two pieces of equipment the author never compromises on are decontamination units and negative air pressure machines. While not physically removing hazardous material, these mobile setups are the vital second line of defence minimising health risks to workers. Here’s what these unsung site heroes do and why they’re mandatory when disturbance activities occur.
Decontamination showers
After removing asbestos materials in disposable suits, workers cannot just peel off PPE and head home still covered in fibres. Likewise, equipment has to be thoroughly decontaminated before leaving the site. Custom mobile shower units provide controlled transitioning from dirty to clean areas ensuring personnel and gear asbestos-free.
Upon entering shower modules, personnel undergo HEPA vacuuming to dislodge surface fibres from suits. After showering completely, disposable clothing is removed avoiding any secondary contact contamination in clean zones. Without such showering protocols, even microscopic amounts of asbestos fibres transferring from site could eventually accumulate in worker homes or vehicles. Over years, this may well result in later-life asbestos diseases.
Negative air machines
If decon showers minimise transporting asbestos fibres externally offsite, negative air pressure units control fibres spreading internally within workspace zones. These machines filter and expel air creating constant airflow from clean to contaminated areas. The air movement also helps avoid worker exposure when handling asbestos.
Units exhausted outside via sealed hoses/trunking means contaminated air cannot migrate building-wide. High-spec HEPA filtration captures asbestos fibres down to 0.3 microns releasing clean air only. The author always mandates doubled units as backup ensuring constant pressure differentials if any machine faults arise. Otherwise “still zones” and swirling eddies could see fibres on the move and put personnel having removed PPE at risk.
Vital, mandatory equipment
Too often over the years arguments against providing such equipment occur due to hire costs and site logistics. But the author has stood firm that asbestos exposure prevention is about layers of control. Primary removal controls like wet methods aim to hold fibres at source. Decontamination units and negative air machines represent the critical second layer stopping any stray fibres left uncontrolled.
This 1-2 punch is essential otherwise it’s only a matter of time before worker concentrated exposure amasses into health issues decades later. Don’t ignore this hard-learned lesson that the author and other asbestos veterans now face consequences from. Mandate such safety layers on every job to avoid preventable illness repeating itself into the future.
Shower unit features
Well-designed asbestos decontamination units have features like:
- Multiple connected modules segregating clean/dirty areas
- Floor drainage grates to contain shower runoff
- Laminar shower heads that bathe suits thoroughly
- External power connections for plug-in tools like vacuums
- Ramps and stairs assisting access/egress for workers
Air unit specifications
When selecting negative air machines, key technical specifications include:
- High airflow rate measured in cubic metres per hour
- Low noise emissions to maintain onsite communication
- HEPA filtration down to 0.3 microns capturing asbestos fibres
- Dual filtration stages prolonging filter life
- Fault warning lights indicating loss of containment integrity
Asbestos fibre dynamics
Once released from source materials, asbestos fibre aerodynamics heavily influence potential exposure such as:
- Shape and aspect ratio – Thin fibres resist settling
- Electrostatic charge – May attract and bind other particles
- Air turbulence – Can keep airborne fibres suspended for longer durations
Conclusion
After managing numerous asbestos removal jobs over 20+ years, the author insists decontamination stations and negative air machines represent fundamental exposure precautions. Ignore them at your peril. Unit hiring costs are minor compared to one asbestos disease claim down the track. Their operation filters both personnel and ventilation systems ensuring no uncontrolled fibre migration from contaminated zones. Treat them as mandatory.
