PPE guide: a head start

There are more than 30 British Standards covering helmets, so choosing the right one for the right circumstance, although sometimes confusing, is essential.

Employers must, by law, provide adequate and suitable head protection and ensure it is worn if there is a risk of injury to the head, which will be the case on many work sites.

They must also comply with the requirements of the Personal Protective Equipment (PPE) Regulations 1992, which were amended in April 2013 to cover the provision and use of head protection on construction sites, when the Construction (Head Protection) Regulations 1989 were revoked.

But what is adequate head protection? The PPE Regulations fail to explain this, leading to uncertainty and an increased risk of injury if inappropriate head protection is selected.

To assess the risk, several aspects of the working environment should be examined, such as:

• the probability of falling objects

• whether falling objects could strike any worker's head

• the possibility of workers walking into objects at head height

• the possibility of swinging loads

• the likelihood of slips, trips and falls

• the possibility of a worker falling from a moving object, such as a vehicle.

Once the measures at the top of the control hierarchy have been exhausted -- removing or minimising the risk where possible -- what remains is to consider the residual risk, assessing both the likelihood and the severity of potential harm. If the hazard comprises a huge rock, the severity will be massive. But if it is a small pebble, the severity will be low, even if it is very likely that a pebble will fall. In the latter case, a lightweight helmet will offer sufficient protection. In low likelihood, high severity situations, a high-performance helmet will be more suitable.

An electrician fitting out a building in a ventilated helmet could find small conductors poke through ventilation holes

Construction site scaffolding, for example, should have features such as kickboards, edge netting, and a bladder or skirt between it and the building to catch anything that might fall. With these precautions a lightweight helmet for low-risk environments is fine.

Range finding

The different types of helmet used in construction and industry, and the environments in which they are most suitable, are as follows:

• EN 812 bump cap: A close-fitting baseball cap style offering the lowest level of protection. As the name suggests, its function is to provide padded protection against knocks from static objects. The EN 812 standard test for shock absorbance from an impact involves a 5 kg mass dropping 25 cm on to a head form covered in the cap from the side, above and behind. The force transmitted through the cap must be no more than 15 kilonewtons (kN). To pass a penetration test to check efficacy against sharp objects, a 500 g conical striker must not breach the head form when it is dropped 50 cm on to the cap.

• EN 397 standard safety helmet: This will be suitable if a falling object could hit the head, and is the most common type of helmet used in the workplace. The EN 397 shock absorbance test again involves a 5 kg striker but dropped on to the helmet from 1 m. The maximum force reaching the head form underneath must not exceed 5 kN. In the penetration test, a 3 kg conical striker is dropped from a height of 1 m.

• EN 397 lightweight helmet: In recent years, lightweight helmets have become more popular. Being light, there is less material in them, so they are useful when there is a very low risk of anything falling on the head, such as in low-rise construction, utilities and highway maintenance. For someone working on the side of the roadway, or telephone or electrical engineers inspecting a cabinet, or a worker lifting a duct cover in the road, there is no actual danger of anything falling, but a helmet is needed in case a stone or another loose object flies up and hits their head.

• EN 397 industrial safety helmet: The more traditional model usually weighs around 400 g to 500 g with a robust shell of uniform thickness. This is ideal for applications such as workers excavating foundations in a hole, where there is a chance that something may fall on them from the side as well as the top and hit them on the head.

• EN 12492 climbing helmet: Also known as mountaineering helmets, these can also meet the EN 397 impact protection requirements, in some cases having extra padding for side-impact loads. This type of helmet has become popular with scaffolders to protect them from hazards such as swinging pieces of tube. They also have a secure chinstrap, which will keep the helmet on the head should the wearer fall from height. EN 12492 shock absorbance tests involve extra impacts at the front, side and rear of the helmet using 5 kg flat and hemispherical strikers, each weighing 5 kg. The transmitted force through the head form cannot exceed 10 kN. The penetration test is similar to that for EN 397 but the strike test is applied to a bigger area of the helmet.

• High-performance EN 14052 industrial safety helmet: This is intended for use on sites where objects and debris are likely to fall, such as in mining and quarrying. Impact tests on the crown of the helmet under EN 14052 use a 5 kg mass dropped about 2 m, or 1 m for off-crown impacts. For penetration, a 1 kg blade is dropped onto the helmet from 2.5 m (crown impacts) or 2 m (off-crown impacts) and no contact with the head form is permitted.

A high-performance helmet is ideal for demolition work, but would be overkill working on the highway

Balanced choice

No one helmet is perfect for everybody and there are several trade-offs to consider when deciding which is right for a work environment. First is the trade-off between performance and comfort. High-performance helmets are relatively heavy, and though they offer maximum protection, unsupervised wearers may be tempted to remove the more cumbersome designs, leaving them with no protection at all.

So you need to balance protection with comfort. A high-performance helmet is ideal for demolition work, but would be overkill when working on the highway.

In the case of electrical insulation inspection, if ventilation is put into a helmet to keep the inspector's head cool, it reduces its electrical insulation performance. An electrician fitting out a building in a ventilated helmet could find that the conductors, which are small, poke through ventilation holes.

But for an energy supply engineer working at height on a pylon, having an insulated head may be immaterial. In these circumstances, it would be better to have some comfort, since it is unlikely a conductor, which is thicker than a domestic cable, would penetrate the ventilation holes.

The need for retention on the head is another factor to consider when choosing a helmet. Climbing helmets are designed to stay on the head should there be a rock fall, with an unbreakable chin strap. In a quarry or in demolition, if one rock falls down it is likely to be followed by more, so the climbing helmet is safer. But in a factory, falling tools or materials are likely to come singly, so a helmet with a chin strap designed to break should be chosen to avoid the danger of the worker being dragged into machinery by their helmet.

Some helmets combine properties. For example, in a refinery in Europe, workers are using a helmet that meets both the requirements of EN 12492 and the shock absorption requirements of EN 397, as they move around the site by bicycle. Conventional cycle helmets were not deemed suitable for their work around hazardous equipment.

Choosing the right helmet for the job involves careful identification of the risks. Wearers must also be trained in how to look after their helmet, so that they will be as safe as possible in carrying out their work duties.