In brief
The installation and maintenance of HVAC systems is in the very hazardous class on the 2025 NACE list; this means a class A specialist, refresher training every year, an annual periodic examination and a risk assessment renewed every two years. The main risks for air conditioning technicians are installing outdoor units at height, maintenance work on roofs, the asphyxiating, freezing and flammable effects of refrigerant gas, hot work during brazing, and electricity. A technician working with fluorinated gases must also hold a VQA (Vocational Qualification Authority) vocational qualification certificate.
Why is HVAC installation and maintenance in the very hazardous class?
A workplace's hazard class is determined by the NACE code of its main activity. On the list fully renewed with NACE Rev.2.1 on 13 March 2025, the installation and maintenance of heating, ventilation and air conditioning (HVAC) systems (43.22.06 and 43.22.07) is in the very hazardous class. This classification comes from the nature of the work: on the same day a technician works at height, brazes, handles pressurised gas and electricity, and is often on another employer's site or building.
The main obligations the very hazardous class places on air conditioning and ventilation companies are:
| Obligation | Requirement in the very hazardous class |
|---|---|
| OHS specialist | Class A certificate; at least 40 minutes per employee per month |
| Workplace physician | At least 15 minutes per employee per month |
| Other health personnel (DSP) | Mandatory with 10 or more employees |
| Basic OHS training | At least 16 hours; job-specific risks delivered face to face |
| Refresher training | Every year, at least 8 hours |
| Periodic examination | Every year |
| Risk assessment and emergency plan | Renewed at least every 2 years |
For the details of this table see our article on very hazardous workplace obligations, and for how to find your code see how to find your hazard class.
Air conditioning technician safety: risks by stage of the job
HVAC installation risks do not arise at a single moment; they appear differently at each stage of the work. Breaking the risk assessment down into stages, instead of passing it with a single line reading "air conditioning installation", makes the controls concrete.
| Stage | Main risk | Key control |
|---|---|---|
| Survey and measuring | Falls on roofs, facades or suspended ceilings | Access route determined in advance, never going up alone |
| Carrying and lifting | Heavy outdoor unit, carrying on stairs, back strain | Lifting aid, two-person carry, crane or platform |
| Installation and drilling | Work at height, dust, noise, hidden electrical cables | Platform and harness, drilling with dust extraction, cable detection |
| Pipe connection and brazing | Burns, fire, oxy-fuel cylinder risks | Hot work permit, extinguisher, cylinders kept upright and secured |
| Pressure test, vacuum and gas charging | Pipe bursting under pressure, gas leak, frostbite | Nitrogen test with a regulator, goggles and gloves, ventilation |
| Commissioning and maintenance | Electric shock, rotating fan, hot surfaces | Energy isolation and lockout, waiting for capacitors to discharge |
Air conditioning installation at height: facades, balconies and outdoor units
Mounting the outdoor unit on a facade, outside a balcony or on a high bracket is the job in which air conditioning technicians suffer their most serious accidents. Leaning out of a window or over a balcony railing to work is the precaution most often skipped with the excuse that "it will only take a minute".
If air conditioning installation is to be done at height, the following order is followed:
- Collective protection first: Can a suitable mobile elevating work platform, facade scaffold or fixed working platform be used? For choosing platforms and scaffolds see our article on scissor lifts and boom platforms.
- Fall arrest if collective protection is not possible: A full-body harness is used with a lanyard attached to a suitable anchor point. A balcony railing, an air conditioning bracket or a window frame is not an anchor point. For details see our article on anchor points and lifelines.
- The area below is protected: As the outdoor unit, tools or screws may fall, the area below the facade is cordoned off and pedestrian traffic is diverted.
- A rescue plan is ready: How a technician left suspended in the harness will be brought down is known in advance.
For the general rules of working at height you can read our article what is work at height. The fitness of a technician to work at height is assessed by the workplace physician.
Rooftop air conditioning maintenance and rooftop units
Packaged air conditioners and air handling units on the roofs of factories, shopping centres and warehouses need regular maintenance. The risks in rooftop air conditioning maintenance are:
- Fragile surfaces: Skylights, roof lights, old corrugated sheets and insulation panels may not bear a person's weight. They are either protected or a walkway is defined so that nobody steps on them.
- Edge openings: If the unit is close to the roof edge, edge protection or a lifeline is needed.
- Access: There must be a fixed ladder or a safe hatch to reach the roof; portable ladders must not be used without being secured.
- Weather: Strong wind, icing and summer heat postpone roof work.
- Lone working: A technician working alone on a roof must have a regular communication arrangement.
For general roof risks see our article on roof work and solar power plants. If the maintenance is carried out in another employer's building, that workplace's work permit and coordination rules also apply.
Refrigerant gas hazards: asphyxiation, frostbite, flammability and decomposition
Refrigerant gases are often thought to be "harmless". In fact they have four separate hazards:
- Asphyxiation: Most refrigerant gases are heavier than air. They can accumulate in low, enclosed places such as basements, plant rooms, ducts and pits and reduce oxygen. After a major leak these areas are not entered without ventilation; gas measurement is carried out where necessary. For confined space rules see our article on working in confined spaces.
- Frostbite: Contact of liquid refrigerant with skin or eyes causes an instant cold burn. Safety goggles and gloves are worn during charging and recovery.
- Flammability: Some refrigerants used in new-generation equipment are in a lower flammability class (e.g. R32, A2L), while others are highly flammable (e.g. R290 propane, A3). With such equipment ignition sources are controlled, ventilation is provided and the manufacturer's service instructions are followed.
- Decomposition products: When fluorinated refrigerants come into contact with a flame or hot surface, they can decompose into toxic and corrosive products such as hydrogen fluoride. For this reason no brazing is done on a line containing refrigerant; the gas is first recovered in accordance with the rules.
Only nitrogen with a regulator is used for pressure testing; pressure tests are never carried out with oxygen or air. Gas cylinders are transported upright and secured and are kept away from flames or direct heat sources.
Electricity and hot work
Connecting outdoor and indoor units, control boards and the compressor supply all carry electrical risk. A technician must not work on a terminal box without isolating and locking out the energy themselves and verifying the absence of voltage by measurement. The capacitors on inverter unit boards can remain charged for some time after the power is switched off; the waiting time in the manufacturer's instructions is observed. For lockout and tagging see our article on LOTO, and for the question of authorisation see who may carry out electrical work.
Brazing copper pipe uses an oxy-fuel or propane flame. The work area is cleared of flammable insulation, wood or cardboard, an extinguisher is kept nearby and the area is watched for a while after the job is finished. Brazing done in a factory or office building is subject to that workplace's hot work permit; see hot work permit.
Training, health surveillance and certificate checks
In short, what an air conditioning and ventilation company must do for its own employees is:
- Basic training of at least 16 hours; the section on job- and workplace-specific risks is delivered face to face and in practice. Refresher training is given every year.
- The periodic examination is carried out every year; work at height and, where relevant, noise exposure are included in the physician's assessment.
- The VQA certificate of every technician working with fluorinated gases is kept on file and its validity is tracked.
- If a technician goes to a customer's workplace in the hazardous or very hazardous class, under Art. 17/5 of Law No. 6331 on Occupational Health and Safety they may not start work without a document showing they have received training on the risks of the job they will do. Keeping training certificates ready at hand prevents delays on site.
In Bursa and the surrounding provinces we carry out site risk assessments and training plans for HVAC, building services and maintenance companies as part of our OHS specialist service. For other risks in a construction site environment see our construction page.
Frequently Asked Questions
What hazard class is an air conditioning installation company in?
Under the 2025 list, the installation and maintenance of HVAC systems (NACE 43.22.06 and 43.22.07) is in the very hazardous class. If the company's main activity falls under these codes, all obligations of the very hazardous class apply.
What certificate must an air conditioning technician hold?
Anyone who installs, maintains or services stationary refrigeration and air conditioning equipment containing fluorinated greenhouse gases must hold a VQA Vocational Qualification Certificate under the Regulation on Fluorinated Greenhouse Gases. In addition, there should be an OHS training certificate and a periodic examination record.
Is a safety harness enough when installing an outdoor unit?
Collective protection such as a mobile elevating work platform or scaffold is considered first. A harness is used if collective protection is not possible and it can be attached to a suitable anchor point. A balcony railing and an air conditioning bracket are not anchor points.
What should be done in a refrigerant gas leak?
The area is ventilated, ignition sources are removed and enclosed or low-lying areas are not entered without ventilation. Oxygen and gas measurements are taken if necessary; after the leak is fixed, the gas is recovered in accordance with the rules.
A certified specialist matched to your hazard class: site inspections, approved logbook, training plan, annual plan and report follow-up.
Bursa SİSTEMER OSGB Technical Team — written from the field experience of our OHS specialists and workplace physicians. Legal information is valid as of the publication/update date; contact us for an assessment specific to your business.