High Purity Water System Installation SWMS
SWMS variants reference your state’s WHS legislation. Instant download after payment.
High purity water system installation is high risk construction work in New South Wales because of what is used to keep the water clean rather than because of the water. Section 291 of the Work Health and Safety Regulation 2025 (NSW) captures the work under the contaminated atmosphere category, the confined space category, the energised electrical category because commissioning necessarily energises, and the pressurised chemical line category. A safe work method statement is required under section 299. SafeWork NSW is the regulator.
A high purity loop is engineered to exclude biological growth, and the three methods of doing that are the three things that hurt people here: ozone, hot water at 80°C and above, and chemical sanitisants. All three appear only at commissioning and service, which is exactly when the crew is on the equipment.
Ozone is the one that is consistently underestimated, because the plant makes its own. Ozone is not delivered in a cylinder that someone signs for — it is generated on site, on demand, by a generator in the plant room, from the air or oxygen feed. It is a powerful oxidiser with a very low workplace exposure standard, and a leak or a vent into an enclosed plant room reaches harmful concentration quickly. Its sharp odour is detectable well below the exposure standard, which sounds protective but is not: the smell fades with exposure, so a crew that has been in the room for twenty minutes stops noticing it while the concentration keeps rising. Nothing about ozone control in this SWMS depends on smelling it.
Hazards identified
14 hazards covered, sorted by priority.
Respiratory injury or fatality — ozone is a strong oxidiser and the plant generates its own
Fatality — ozone accumulation, oxygen displacement and residual sanitisant in one tank
Full-thickness scald in seconds — an 80°C loop, in plastic pipe that gives no visual warning
Severe chemical burns to skin and eyes, and fume accumulation in an enclosed plant room
Fatality — electrocution during commissioning in a plant room that is a wet room by design
Fatality or serious injury — the loop is designed to run itself and starts on level, conductivity or a timer
Eye and skin injury from an intense UV lamp, with symptoms delayed several hours
Serious injury — a cap or fitting released as a projectile during pressure test
Fatality — crush injury from the skid or vessel during placement in a restricted plant room
Burns from the fusion tool, and fume from heated PVDF or PP in an enclosed space
Slips and falls — a high purity plant room is a wet room by design
Fire or ignition — oxygen and hydrocarbon in contact on the generator feed
Permanent noise-induced hearing loss in a hard-surfaced plant room
Musculoskeletal injury from handling vessels, resin drums and spools between skids
Control measures
Hierarchy-of-controls order: elimination → substitution → isolation → engineering → administrative → PPE.
- 1Isolate and lock out the ozone generator and purge the system to ambient before any break-in, connection, filter change or entry — the plant makes its own ozone, so there is no cylinder to remove and no delivery to refuse.
- 2Monitor ozone continuously in the plant room with an alarm and an interlock that shuts the generator down, and fit destruct units on every vent.
- 3Never permit any control to depend on smelling ozone — the odour is detectable below the exposure standard but fades with exposure, so a crew that has been in the room stops noticing while the concentration rises.
- 4Treat the storage tank as a confined space with testing for oxygen AND ozone, permit, standby person who does not enter, and rescue in place before entry.
- 5Isolate and lock out the ozone generator, recirculation pump, UV, hot water sanitisation and every inflow before entry — no entry while any sanitisation regime on the connected loop is running or armed.
- 6Interlock the hot water sanitisation cycle so it cannot start while a break-in permit is open, and verify the loop at ambient before any connection or sample point is opened.
- 7Recognise that an 80°C loop causes a full-thickness scald in seconds and that PVDF and PP do not look hot — verify status physically, never from a control screen.
- 8Dose from sealed containers through closed transfer and metering pumps rather than decanting, with eyewash and safety shower to AS 4775 within reach of the dosing point.
- 9Segregate incompatible chemicals and never dose into a common line without verifying compatibility, and add acid to water and never water to acid.
- 10Complete all installation, termination and pre-energisation verification dead — energised work is prohibited under Part 4.7 Div 4 ss.154 & 157 unless de-energisation is not reasonably practicable.
- 11Isolate and lock out the pump, UV, ozone generator AND the automatic start path — level, conductivity and TOC signals, timers and the BMS — because a high purity loop is designed to run itself.
- 12Isolate and lock the UV supply before any chamber, sleeve or lamp is opened, never bypass the chamber interlock, and never energise a lamp outside its chamber for any reason including testing.
- 13Test hydrostatically rather than pneumatically wherever AS 4041 and the designer permit, to the manufacturer's rating for the material at the test temperature.
- 14Reverse and record any interlock or automatic-start defeat before the crew leaves, and notify the facility — a defeated ozone interlock is a plant room with no gas protection.
Applicable Codes of Practice
The benchmark for ozone and the sanitisation chemicals as hazardous chemicals, including the workplace exposure standards and the control of exposure.
The benchmark for entry permits, testing, ventilation, standby and non-entry rescue where the storage tank is entered — the atmospheric test must include ozone.
The benchmark for isolation, testing for dead and the conduct of energised commissioning — in a plant room that is a wet room by design.
Confined space classification, atmospheric testing, entry permits, standby arrangements and non-entry rescue.
The installation, connection, backflow protection and materials requirements where the system connects to a potable supply.
The fabrication, support, inspection and pressure testing requirements for the distribution loop and skid pipework, including the material's rating at test temperature.
High-Risk Construction Work triggered
A high purity water storage tank is a confined space with restricted egress where ozone accumulates, oxygen can be displaced and residual sanitisant remains. Entry occurs for inspection, cleaning and internal connection.
Peracetic acid, caustic, acid and biocide are dosed and circulated through the system under pressure, and the distribution loop is pressure tested and connected as a chemical line.
Commissioning necessarily energises the skid, pumps, UV and ozone generator, and the plant room is a wet room by design — this is the category that makes the work high risk construction work rather than a specialist install.
Ozone is generated on site by a generator in the plant room and has a very low workplace exposure standard; sanitisation chemicals add fume to the same enclosed space.
RO/DI skids, tanks and vessels are craned and placed into restricted plant rooms where the load travels close to fixed structure.
Carrying out high risk construction work without a compliant SWMS is an offence under the Work Health and Safety Regulation 2025 (NSW). An ozone exposure or a confined space fatality in a storage tank attracts immediate SafeWork NSW attention, and the SWMS is the first document requested. Where the SWMS relies on odour as an ozone control, it is evidence the PCBU did not understand the substance its own plant was generating.
Who this is for
- →Plumbing contractors installing RO/DI, WFI and high purity distribution systems
- →Pharmaceutical, biotech and laboratory fitout contractors delivering purified water plant
- →Dialysis and healthcare contractors installing water treatment for patient-connected use
- →Food, beverage and semiconductor contractors installing high purity process water
- →Principal contractors and facility managers required to obtain and review a SWMS before commissioning starts
What you receive
- ✓A complete, editable Safe Work Method Statement authored for New South Wales — the WHS Act 2011 (NSW), the WHS Regulation 2025 (NSW), and SafeWork NSW as regulator, with correct section numbers throughout
- ✓14 identified hazards with initial and residual risk ratings on a 5x5 matrix, each with the full hierarchy of control from elimination through to PPE
- ✓The ozone control set built on the fact that the plant generates its own — there is no cylinder to refuse — with monitoring, interlock and destruct units on every vent
- ✓The explicit rule that no ozone control may depend on smell, because the odour fades with exposure while the concentration rises
- ✓The hot sanitisation control set — an 80°C loop in plastic pipe that gives no visual warning, with the cycle interlocked against an open break-in permit
- ✓The automatic-start isolation control set covering level, conductivity and TOC signals, timers and the BMS, because a high purity loop is designed to run itself
- ✓The full high risk construction work breakdown — contaminated atmosphere, confined space, energised electrical, chemical lines and mobile plant — with the reason each category applies
- ✓A PPE matrix mapping each task to the required equipment and Australian Standard, including personal ozone monitoring in the plant room
- ✓Microsoft Word (.docx) format, unbranded, editable fields for PCBU, ABN, site, dates and worker sign-on
Worked example
A technician is changing a filter cartridge on a purified water loop at a dialysis unit. The system has been sanitising overnight on ozone. He isolates the housing, drains it, and opens it. The ozone generator is not running at that moment — the cycle finished two hours ago — so nobody isolates it, and the residual ozone in the loop vents into the plant room when the housing opens. He notices the sharp smell and thinks nothing of it; the room always smells faintly like that. Twenty minutes later he no longer notices it at all, and takes that as the room clearing. It is not. Ozone deadens its own detection with continued exposure while the concentration in a poorly ventilated room keeps climbing. He finishes the job with a headache and a cough that gets worse overnight. The controls in this SWMS break that chain at the start. The ozone generator is isolated and locked out and the system purged to ambient before any break-in, connection or filter change — not merely confirmed as 'not currently running', because the residual in the loop is the exposure. Continuous ozone monitoring with an alarm and a shutdown interlock covers the room, so the release is detected by an instrument rather than by a nose. And the document states plainly that no control may depend on smelling it, because the fading odour reads as reassurance at exactly the moment it should not.
Related legislation
- Work Health and Safety Act 2011 (NSW) — Section 19 primary duty of care, extending to facility occupants where the system serves a hospital, dialysis unit or laboratory; Section 47 consultation; Sections 35–38 notifiable incidents
- Work Health and Safety Regulation 2025 (NSW) — Section 291 high risk construction work; Section 299 SWMS required and content prescribed; Section 302 review
- Work Health and Safety Regulation 2025 (NSW) — Part 4.3 Division 2: confined spaces, where the storage tank is entered
- Work Health and Safety Regulation 2025 (NSW) — Part 4.7 Division 4, sections 154 and 157: energised electrical work is prohibited unless de-energisation is not reasonably practicable; commissioning is a recognised exception requiring a documented method and a second person
- Work Health and Safety Regulation 2025 (NSW) — Chapter 7: hazardous chemicals, including the workplace exposure standard for ozone
Frequently asked questions
Why is ozone treated differently from other gas hazards?
Because the plant generates it on site, on demand, from the air or oxygen feed. There is no cylinder anyone signs for, no delivery to refuse and no obvious source in the room — which is why crews consistently underestimate it. It is a powerful oxidiser with a very low workplace exposure standard, and a vent or leak into an enclosed plant room reaches harmful concentration quickly.
The room smells of ozone but the smell goes away. Is it clearing?
No, and this is the specific trap the SWMS is built around. Ozone's odour is detectable well below the exposure standard, which sounds protective — but the sense fades with continued exposure. A crew that has been in the room for twenty minutes stops noticing it while the concentration keeps climbing. The document states that no ozone control may depend on smelling it; detection is by instrument, with an alarm and a generator shutdown interlock.
The ozone cycle finished hours ago. Do we still need to isolate the generator?
Yes. Isolation and lock-out of the generator plus purging the system to ambient is required before any break-in, connection, filter change or entry — not merely a check that it is not currently running. The residual ozone held in the loop is the exposure, and it vents into the room the moment a housing or connection is opened.
Why does the SWMS treat hot water sanitisation as a major hazard?
An 80°C loop causes a full-thickness scald in seconds, and PVDF and PP give no visual warning that they are hot — there is no colour change and no radiant heat you notice before contact. The SWMS interlocks the sanitisation cycle so it cannot start while a break-in permit is open, and requires the loop's status to be verified physically at the pipe rather than read off a control screen.