Safe maintenance - hazards

This area outlines some of the hazards associated with maintenance work.


This will depend on the work you are doing and where you are doing it. The hazards are commonly grouped as physical, chemical, biological and psychosocial. The hazards may vary significantly between planned preventive and repair or corrective maintenance tasks. It is essential that maintenance workers and those supervising the works understand potential consequences of their actions or their lack of attention to detail.

Type of Hazards


  • mechanical movement - rotating elements e.g. flywheels; compressed springs; gravity; unexpected startups e.g. blockages cleared, trapped air in lines operating valves, restoration of power, computerised auto-start; instability; failure of sub-standard parts; homemade machines
  • electrical - capacitors; high voltage; static
  • hydraulics - high pressure fluids
  • pneumatic - high pressure steam, gases, vapours
  • engulfment - oxygen deficient atmospheres; radiation
  • fire/explosion - extreme heat/cold; noise; vibration
  • work at Height - weather; animals; ergonomics; visibility.


  • dusts & fibres e.g. asbestos, silica, respiratory sensitizers
  • dangerous substances e.g. chlorine, oxygen, hydrogen
  • toxic, oxidizing, explosive, flammable, corrosive
  • hydraulic fluids, oils, acids, alkalis, organic solvents.


  • pathogenic bacteria, viruses, parasites, moulds and fungi.


  • time pressure; long hours; shift work
  • poor work organisation; unsocial working hours.

Asbestos - the single greatest cause of work related deaths in the UK

Anyone who works on the fabric of a building may be at risk of disturbing asbestos. This includes electricians, joiners, plumbers, handymen, gas fitters, shop fitters, heating and ventilation engineers, plasterers, labourers, roofers, surveyors, general maintenance engineers and phone and data engineers.

HSENI's hidden killer section helps tradesmen and maintenance workers know when they might be working with asbestos.

It is only when asbestos containing materials (ACM) are disturbed, or the materials become damaged that it becomes a hazard.

HSENI's duty to manage section explains how you can go about managing asbestos to protect yourself and others from exposure to asbestos fibres.

Asbestos could be present in any building that was built or refurbished before the year 2000. Typical locations of asbestos in domestic properties include:

  • textured coating e.g. artex
  • rainwater items
  • house insulation
  • water tank
  • toilet cistern
  • wall panelling
  • fuse box
  • floor tiles
  • heater cupboard


Isolation is about keeping people separate from work hazards during maintenance.

These work hazards are commonly grouped as physical, chemical, biological and psychosocial. They may vary significantly between planned preventive and repair/corrective maintenance tasks.

When considering isolation, there is a need to assess the danger zone and prevent danger to any person(s) who is in, or may enter it.

Communication is essential particularly when staff changes for example breaks or shift handovers occur. Often maintenance work is done by contractors who need to be adequately supervised.

Isolation of the energy and power sources is essential. Any stored energy (hydraulic or pneumatic power, for instance) should be dissipated before the work starts.

Before entering or working on the equipment, it is essential that the effectiveness of the isolation is verified by a suitably competent person.

What to take account of


A clear safe system of work is essential. It must define:

  • the workplace's hazards and who may be affected 
  • state what method of isolation is to be used 
  • define the training and information for competent workers
  • state how the work is to be managed and communicated
  • state how the effectiveness of the isolation system is to be tested before starting the maintenance work
  • must cover emergency situations.

Safe stop

Safe stop is probably the most important safety action of all when operating self-propelled machinery such as tractors, forklift trucks, lorries. These essential simple steps can be applied across all industries.

Physical guards

Physical guards protect maintenance workers and other unauthorised people from the hazards within the danger zone. They may be simple fencing, barriers, rope or purpose built machine guards or robust cattle handling facilities.

Where guards are removed or access is required inside guarding, then measures are needed to prevent access to exposed hazards.

Personal Protective Equipment (PPE)

Appropriate personnal protective equipment (PPE) must be available and used. Many entanglement accidents occur because of loose clothing coming into contact with moving parts of machinery. Often maintenance work increases the risk level e.g. dust exposure levels may be significantly higher for maintenance workers meaning respiratory protective equipment is required.

Permits to work

Permits to work are used to co-ordinate activities, to communicate with all parties involved and to control the risks. The link provides details on using a permit to work as part of your safe system of work.


The method of effective Isolation uses a padlock, or multi-padlock hasps and signage to prevent accidental switch on and to clearly show maintenance work is in progress. It is useful for isolating electric power sources, valves for piped services and materials supplies. It can be effectively applied where more than one maintenance worker is present and where there are shift handovers.


Unplugging may be all that is required to isolate a piece of equipment. Ensure the maintenance person retains control of the plug, so the equipment cannot be inadvertently switched on.


For more information on this topic view the following publications: 

Working at heights

Work at height means work in any place where, if precautions were not taken, a person could fall and injure themselves. The fall could be from one level to another including from ground level into an opening in a floor or hole in the ground.

Many maintenance activities take place at height, such as replacement of high level lighting, cleaning of roofs and repair of roof-mounted equipment.

Using Ladders

A third of all reported fall-from-height incidents involve ladders and stepladders – on average this accounts for 14 deaths and 1200 major injuries to workers each year (GB statistics). Many of these injuries are caused by inappropriate or incorrect use of the equipment.


  • properly assess the job to determine what equipment should be used. Ladders are often used for tasks which could be done more safely and more quickly from equipment such as a cherry picker or a scaffold. Only use ladders for low risk, short duration tasks or where other working platforms cannot be accommodated on the site
  • check the ladder for defects
  • make sure the ladder is only used by people who know how to use it correctly
  • if a ladder is to be used make sure that it is secure and cannot slip. Tie it at the top, have someone hold it at the base, or use a suitable stability device to prevent it from slipping
  • if the ladder is more than 5 m long, a person at the base is unlikely to be able to stop it from slipping
  • place the ladder on a firm, stable surface which is of suitable strength to keep the rungs horizontal
  • consider using attachments such as an adjustable ladder leveller, or a 'stand' spreader bar
  • set the ladder at the correct angle. It should be angled out one measure for every four up (75 degrees)
  • use a ladder that is, or can be, extended to the correct length - don't work from the top three rungs of the ladder. Make sure the ladder protrudes sufficiently above the place of landing to which it provides access - three rungs or 1 m should be enough

The following publication outlines information on the safe use of ladders and stepladders:

Roof Work

Roof work is an intrinsically high-risk activity because it involves working at height. People working on roofs account for a large number of deaths every year caused by from falling from height whilst at work, and falls through fragile materials, such as fragile asbestos cement roofing sheets and roof lights account for more deaths than any other single cause.

Remember that roof work is not just an issue for trained roofers or construction companies; other workers, such as building supervisors may be accessing the roof as part of their work in maintaining a building.

Planning work is vital to ensure the safety of staff in all roof work, from short duration maintenance work to major refurbishment. Planning helps to ensure that the work is carried out safely, efficiently and without delay.