On an asbestos enclosure, the negative pressure unit (NPU) is not an accessory. It is the control. Everything else (the sheeting, the airlocks, the signage) only works if the negative pressure unit (NPU) is holding the enclosure under pressure and moving air in one direction, every minute of every shift.
Which is why the choice of negative pressure unit (NPU) deserves more thought than it usually gets. DeconSafe Solutions made that decision once and made it properly: we are the exclusive reseller for Deconta across Australia and New Zealand.
NPU, neg air, negative air: the same machine
Worth clearing up first, because the terminology splits between the office and the site.
Negative pressure unit (NPU) is what the codes of practice, the specifications and the tender documents call it. On site, almost nobody says that. Crews call it a neg air, a negative air machine, or just the negative air, as in "get the neg air running before we seal up." Some people say air scrubber, though strictly that describes a unit recirculating and filtering air within a space, rather than one exhausting an enclosure to outside under negative pressure.
Same piece of plant. DeconSafe Solutions is happy to take the order either way. Whether you ask us for a negative pressure unit (NPU), a neg air, or a negative air machine, you'll get the right unit for the enclosure.
What the code actually asks a negative pressure unit (NPU) to do
Before comparing brands, it's worth being clear about what the law expects, because the specification follows from it.
In Australia, friable (Class A) asbestos removal is governed by the Work Health and Safety Regulation and the Safe Work Australia model Code of Practice How to Safely Remove Asbestos, adopted as an approved Code of Practice in NSW under the Work Health and Safety Act 2011 (NSW) and enforced by SafeWork NSW. Its companion document is the model Code of Practice How to Manage and Control Asbestos in the Workplace.
In broad terms, a friable removal enclosure must:
- be held under negative pressure relative to the surrounding area, with the code working to a differential of around -12 Pa as the practical working minimum
- exhaust through a HEPA filter complying with AS 4260-1997, a standard that, like its European equivalent, spans several efficiency classes rather than fixing one number
- be smoke tested before removal begins, and shown to hold negative pressure with the unit running
- have the pressure differential monitored and the readings recorded as part of the removal records
- be served by a three-chamber, two-shower decontamination unit: dirty end, buffer zone, clean end
- be built and wrapped in polyethylene sheeting of at least 200 µm, with waste double-bagged in 200 µm plastic, sealed and labelled
- be barricaded and signposted with asbestos warning signage
The asbestos workplace exposure standard is 0.1 fibres/mL as an 8-hour TWA, with 0.01 fibres/mL used as the control level for control and clearance monitoring. For Class A work, air monitoring and the clearance certificate must come from an independent licensed asbestos assessor.
Every line above is a requirement on the contractor. But most of them can only be met if the equipment is capable of meeting them, which is where equipment selection stops being a purchasing decision and becomes a compliance decision.
New Zealand readers
The framework is parallel but legally separate. Asbestos work in New Zealand is governed by the Health and Safety at Work (Asbestos) Regulations 2016 and WorkSafe New Zealand's Approved Code of Practice Management and Removal of Asbestos. The technical shape is similar (negative pressure enclosures, HEPA filtration, three-stage decontamination, clearance by a competent independent person) but the Australian codes do not apply in New Zealand, and you should work to the New Zealand instruments. DeconSafe Solutions supplies both markets.
German owned, German designed, German manufactured
Deconta GmbH is based at Im Geer 20, 46419 Isselburg, Germany. Not a German-branded product assembled elsewhere. Designed, engineered and manufactured in Germany, and German owned. Every control panel carries a "Made in Germany" badge, and it means what it says.
Deconta has been manufacturing negative pressure units (NPUs) and asbestos containment equipment for more than 20 years. That matters because negative pressure unit (NPU) design is not a general engineering exercise. Filter seating, pressure integrity, filter loading behaviour, duty cycle under dusty load: these are learned over decades of watching equipment work on real asbestos sites, not modelled in a catalogue.
That manufacturing history is what DeconSafe Solutions brings to asbestos removalists, demolition contractors and hygienists across Australia and New Zealand.
Certified, declared and built to standard
This is the part most suppliers can't produce when you ask for it. Deconta issues a full EC Declaration of Conformity with every unit, and the machines are CE marked.
Directives applied:
- Machinery Directive 2006/42/EC
- EMC Directive 2014/30/EU
- Radio Equipment Directive 2014/53/EU
- RoHS Directive 2011/65/EU
- Protection targets of the Low Voltage Directive 2014/35/EU met
Harmonised standards applied:
- EN 60204-1:2018 Safety of machinery: electrical equipment of machines
- EN 61000-6-2:2005 EMC immunity for industrial environments
- EN 62368-1:2014/AC:2015 Safety requirements for information and communication technology equipment
- EN ISO 12100:2010 Risk assessment and risk reduction
- EN ISO 13849-1:2015 Safety-related parts of control systems: design
- EN ISO 13849-2:2012 Safety-related parts of control systems: validation
- EN ISO 13857:2019 Safety distances to prevent hazard zones being reached by upper and lower limbs
Risk assessment methodology: the machine risk assessment is carried out to EN ISO 12100 and DIN ISO/TR 14121-2, with required performance level (PLr) determined to EN ISO 13849-1 and safety integrity level (SIL) to EN 62061.
Filtration:
- HEPA filter to EN 1822, class H13 or H14: micro glass fibre paper medium, polyurethane potting compound and gasket, handle protection on both sides
- Pre-filter to DIN 24185 / EN 779, quality class G4 / EU4: synthetic medium, 90% degree of separation (Am)
- Two-stage filter system as standard
How EN 1822 lines up with the Australian requirement
Australia does not mandate the European class label, and the Safe Work Australia code does not itself set a fixed efficiency percentage. It simply requires the HEPA filter to comply with AS 4260-1997. Like its European equivalent, AS 4260 classifies filters across a range rather than to one number: EN 1822 rates H13 at ≥99.95% and H14 at ≥99.995% at the most-penetrating particle size, and AS 4260 certifies filters to equivalent classes using its own sodium-flame test method. The Australian classification reference is AS 4260 High efficiency particulate air (HEPA) filters: Classification, construction and performance, with ISO 29463 as the international series.
In practice
Because neither the code nor AS 4260 mandates a minimum class, a filter can be technically "compliant" while sitting well short of true HEPA performance. That's exactly why, for asbestos and hazardous dust work, DeconSafe Solutions specifies Deconta's EN 1822 H14 filter, not H13, and why DeconSafe Solutions supplies the Declaration of Conformity with the machine, so the actual filter class is documented rather than assumed.
Real numbers: the smart dec S 400
Marketing claims are one thing. Here's a published spec sheet, as an example of what Deconta documents for every model:
| Air flow, free-blowing max. | 7,000 m³/h |
|---|---|
| Air flow with H13 filter + pre-filter | 5,400 m³/h |
| Dimensions (L × W × H) | 880 × 720 × 810 mm |
| Weight incl. filter | 88 kg |
| Power | 230 V, 7.0 A, 1.3 kW |
| Ingress protection | IP 54 |
| Ambient range | 0 °C to +45 °C, 70% RH non-condensing |
| Noise at 2 m / 10 m | 80 dB(A) / 62 to 67 dB(A) |
Note that Deconta publishes airflow with the filters fitted, not just free-blowing, and states the measurement tolerance and method (multi-point measurement with a calibrated vane anemometer). That honesty is rarer than it should be, and it's the number you actually need when you're sizing a negative air machine to hold an enclosure at -12 Pa with adequate air movement. These published figures are for Deconta's standard H13 filter; for asbestos and hazardous dust work DeconSafe Solutions specifies EN 1822 H14, and will confirm the resulting airflow for your enclosure before you order.
Built to last, built to protect
Every Deconta unit supplied by DeconSafe Solutions is built fully of metal, lightweight aluminium or galvanised steel, down to the riveted aluminium type plate. No plastic housings to crack when a unit gets dropped off a ute tray, no flex in the body to compromise the filter seal, especially under Australian heat or sun.
This is the practical difference between equipment that survives five years of site abuse and equipment that gets written off after two. A neg air that has been knocked around and no longer seals properly cannot demonstrably hold the enclosure at -12 Pa, and an enclosure you can't demonstrate is an enclosure you can't defend.
A further design detail worth knowing: Deconta's pressurisation technology prevents contaminated ambient air entering the housing, so in principle the unit can even be run inside the contaminated area. Deconta still recommends against it, because the machine then has to be fully decontaminated afterwards, but it tells you how well sealed the housing is.
Sized for the enclosure, from small rooms to industrial volumes
Most suppliers can offer you one negative air machine for a standard domestic bathroom strip-out. Very few cover the whole spectrum.
On Deconta's own figures, the range starts as low as 2,000 m³/h, right-sized for small enclosures, single rooms and confined domestic work where an oversized unit just makes the enclosure impossible to manage, and extends to very high-capacity units in the order of 70,000 m³/h for large industrial enclosures. Where the standard range doesn't fit the job, Deconta can custom manufacture to the requirement, something DeconSafe Solutions arranges regularly for projects with unusual geometry, access constraints or airflow demands.
That range is what allows DeconSafe Solutions to be a genuine one-stop shop for asbestos management and dust management in Australia and New Zealand: the same supplier for the one-room job on Monday and the industrial enclosure the size of a warehouse. Correct sizing is the point. An under-sized unit will not hold the differential, and an over-sized one makes the enclosure unworkable.
Proven on difficult projects
Deconta equipment has been specified on major Australian infrastructure projects, including work associated with the Snowy Hydro 2.0 scheme, where enclosure volumes, access, run times and reliability requirements sit well outside what general-purpose plant handles comfortably, and where equipment failure is not an inconvenience but a stop-work.
The technology that protects workers, the public and the PCBU
Units with the SRE connect control unit are genuinely connected devices, an IoT negative pressure unit (NPU), a connected neg air, that can be monitored and controlled from any internet-enabled PC, phone or tablet via deconta-connect.com. The connect functions are supported as standard in both Australia and New Zealand.
Closed-loop control, not a dial
Negative pressure is measured between the contaminated area and a defined clean-side reference point, and held at setpoint by continuous fan speed control. Volume flow can be controlled the same way. You set minimum negative pressure, minimum volume flow and maximum negative pressure, and the fan tracks it automatically, including separate day and night setpoints on a seven-day schedule, so an enclosure can be run down overnight and back up before the crew arrives.
Recorded pressure data
The code requires the enclosure's pressure differential to be monitored and recorded. Doing that with a clipboard and a manometer twice a shift produces two data points a day and a gap either side of them. Continuous logging produces a record, which is a materially better answer when a regulator, client, neighbour or insurer asks what the enclosure was doing at 2:40pm on a Thursday.
Particle monitoring on the exhaust
A filter sensor monitors particle concentration in the discharge air and triggers a visual and acoustic alarm if roughly 100 particles per litre is persistently exceeded. It distinguishes a high dust load (many particles in a short time) from a low dust load (a few particles over a long period), and readings can be graphed and recorded.
Alarms that matter
Minimum negative pressure not achieved. Minimum volume flow not achieved. High dust load. Low dust load. Filter pressure at limit, with a settable alarm threshold and a fixed factory red zone. Filter change is flagged on the display before performance falls away.
Live data for the duty holder
Operating hours, actual current, actual power and cumulative kWh, plus GPS and GPRS device tracking and time-zone-aware logging. Under WHS law the PCBU has to demonstrate that a control was implemented and maintained, not just installed. Continuous recorded data does exactly that.
Service, filters and certification: not optional
Deconta is explicit in its own documentation: ventilation plant used for negative pressure maintenance must be serviced as required and at least once a year, repaired where necessary, and inspected by an expert, with test results available on request. Units with SRE connect control should additionally be checked and calibrated annually by Deconta service.
Alongside that:
- The appliances have only been tested with original Deconta HEPA filters. Fitting anything else means machine safety can no longer be guaranteed, with a real risk of leakage or filter rupture releasing hazardous dust.
- Filters must only be changed with the unit switched off, by authorised persons in appropriate PPE, and disposed of as regulated asbestos waste.
HEPA filter integrity testing. The Australian code requires HEPA filtration to be effective and plant to be maintained without risks to health and safety; it does not set a fixed test interval. Industry and occupational hygiene practice is to verify HEPA integrity by aerosol challenge photometer scan, historically DOP and now commonly PAO, at regular intervals, before major jobs, and after any filter change, damage or transport, using a calibrated photometer operated by a competent person such as an occupational hygienist or accredited filter-testing technician. A HEPA filter that has never been integrity tested is an unproven filter, and an inspector will treat it that way.
DeconSafe Solutions doesn't only sell the machine. We supply original Deconta filters, arrange HEPA integrity (DOP/PAO) certification, and provide in-house service and repair across Australia and New Zealand, so the annual inspection, the calibration and the filter records all exist when someone asks for them.
The rest of the enclosure, from the same supplier
Because DeconSafe Solutions is a one-stop shop for asbestos management and dust management, the negative pressure unit (NPU) is only part of what we can put on your site, and the same code-driven logic applies to each item:
- Deconta three-chamber, two-shower decontamination units: dirty end, buffer zone, clean end, as required for friable removal
- Deconta water management and filtration systems, for capturing and treating contaminated water from wet removal and decontamination
- Kasco masks and powered respirators, also exclusive to DeconSafe Solutions. Respirator selection, use and maintenance is governed by AS/NZS 1715, with devices to AS/NZS 1716. Tight-fitting respirators require the wearer to be clean-shaven at the face seal and fit tested, qualitative or quantitative, generally at least annually and whenever the make, model or the wearer's facial features change. Fit testing is how a PCBU demonstrates the RPE actually provides adequate protection.
- H-class vacuums and extraction: Nilfisk, Numatic and Husqvarna, sold and serviced. Dust classes are defined by AS/NZS 60335.2.69, under which class H covers dusts with an exposure limit below 0.1 mg/m³ including asbestos and carcinogenic dusts, with maximum filter penetration of 0.005%. Domestic vacuums are not permitted for asbestos work.
- All consumables and PPE: asbestos warning signage, barricade tape, 200 µm waste bags and sheeting, coveralls, disposable masks, plastic film
- Fit testing before the job starts
- HEPA integrity certification (Dop test) of negative pressure units (NPUs) and H-class plant
- Original Deconta filters and spare parts
- In-house service and repair
A note on silica (Australia)
The same equipment logic now applies well beyond asbestos. In Australia the workplace exposure standard for respirable crystalline silica is 0.05 mg/m³ as an 8-hour TWA, halved from the previous figure in 2020. A national prohibition on the manufacture, supply, processing and installation of engineered stone commenced 1 July 2024, and duties covering the processing of all crystalline silica substances, not only engineered stone, commenced 1 September 2024.
What is changing next:
- Transition to WEL. On 1 December 2026, Australia's Workplace Exposure Standards (WES) will officially transition to a Workplace Exposure Limits (WEL) framework, shifting these figures from enforceable guidelines to strict, hard legal ceilings with increased regulatory penalties.
- Future limit reductions. While the silica limit carries over at 0.05 mg/m³, state WHS regulators and Safe Work Australia continue to review the standard, with long-term policy targets pushing toward a further reduction to 0.025 mg/m³.
Those duties require identifying high-risk crystalline silica work, preparing a silica risk control plan, and applying controls including water suppression, on-tool dust extraction, enclosure or isolation, and respiratory protective equipment, with air monitoring and health monitoring where triggered. In hardware terms that means H-class extraction, on-tool water, negative pressure or enclosure where warranted, and fit-tested RPE, all of which DeconSafe Solutions supplies and services.
New Zealand readers
These particular silica reforms are Australian. New Zealand has no equivalent engineered stone prohibition or crystalline silica processing regulations, so New Zealand readers should work to their own requirements.
Get the right negative pressure unit (NPU), or neg air, for your site
Sizing a negative air machine correctly is the difference between an enclosure that holds -12 Pa all week and one that fights you every shift. Tell DeconSafe Solutions the enclosure volume, the access and the duration, and we'll specify it properly, including supply air, exhaust routing and standby redundancy.
One note on intended use: these units are designed and certified for filtering asbestos-contaminated air and are not suitable for flammable, explosive or hot dusts. If that's your application, talk to us and we'll point you to the right equipment.
Sizing, supply and certification
Tell us the enclosure, and we'll specify the unit
Volume, access and duration is all we need to get the sizing right. Deconta negative pressure units, original filters, HEPA integrity certification and in-house service, across Australia and New Zealand.
Talk to us about your enclosureView the NPU rangeThis article is general information about equipment, not legal or compliance advice. Codes of practice and standards are amended from time to time. Always work to the current version of the Safe Work Australia model codes as adopted in your jurisdiction, or the WorkSafe New Zealand Approved Code of Practice, and confirm requirements with your regulator or a licensed asbestos assessor.
About DeconSafe Solutions
DeconSafe Solutions Pty Ltd is an Australian-based supplier of asbestos management and dust management equipment, serving contractors throughout Australia and New Zealand. DeconSafe Solutions is the exclusive reseller for Deconta negative pressure units (NPUs), also known as neg airs or negative air machines, water management and decontamination systems, and for Kasco respiratory protection, and supplies, sells and services H-class extraction equipment along with the full range of tools, PPE and consumables required to complete hazardous dust work safely.