The work often entails many different types of risks, for example:

• risk of collapse
• risk of confinement
• risk of oxygen deficiency
• risks with air contaminants
• risks with mobile machines
• darkness
• blasting
• ergonomical risks caused by limited working space
• work with health-endangering substances.

This kind of work therefore demands planning of stabilizing measures, ventilation, possibilities of evacuation and rescue of those in emergency, safety areas around machines, enough lighting, safety measures before blasting, firefighting measures, planning of working hours and working rotation during work in limited working areas, that machines are used when possible and that the need for special personal protective equipment is investigated.

Reinforcement of tunnels and rock clearing

When tunnel and rock work is carried out, there is a risk of collapse. To counteract collapse, regular checks and clearing of rock are carried out. The checks and clearing of rock should be carried out by staff with specific competence. In many cases, the rock need to be reinforced.

During rock work, reinforcement is made with, among other things, special rock bolts or through spraying a type of concrete, shotcrete, on the rock. It is important that the shotcrete has time to dry, and that special inspections are carried out before staff is allowed to enter into newly reinforced working areas. Those who carry out reinforcement work, or others who are in an area with risk of collapse, should use a vehicle or machine with a specially reinforced safety roof that protects against a collapse. In the usage stage, the reinforcements need to be possible to inspect regularly.

Air contaminants underground

During blasting or the use of work vehicles, machines and chemical substances underground, one should specifically think about the risks of different types of air contaminants in a confined space.

Regular checks of air quality should be made, for instance with the help of direct-reading instruments and/ or with stationary measuring instruments that warn about air contamination by, for example, quartz and carbon monoxide.

Only diesel-driven engines may be used underground. The vehicles’ exhaust emission control should be regularly checked. During stationary work, the first choice should be electric machines in order to minimize the exhausts. If a truck has a crane that is regularly used, this should be able to be converted to operate on electricity when it is used in a stationary state. Special so-called cabin filters can also be required for certain work vehicles, in order to minimize the risks from quartz dust.

Radon – risk during work underground

Radon is a further risk that exists during underground work. At underground workplaces, the radon level must be measured. Radon is counted as ionising radiation and should be described in the work environment plan.

Fire and evacuation during tunnel work

Fire is one of the most serious risks during tunnel work. A plan for evacuation is required. Existing equipment should be

• escape masks
• fire-extinguishing equipment in vehicles and in different places in the tunnel
• access to a rescue chamber if the evacuation path is long.

Preventive fire protection work is especially important underground. It includes:

• the introduction of new employees
• evacuation drills
• inspection of the storage of flammable material
• checks of vehicles´ fuel-lines and much more.

During most underground work, special coordination with the local rescue services can be required in order to ensure possible firefighting and evacuation of those in distress.

For safe evacuation and localization of those in distress, a system is required that notifies who is in the tunnel and where. Today there are electronic systems with specific positioning functions, which we at the Swedish Work Environment Authority often make demands about.

Laying pipes – partly or completely underground

There is other work that is carried out completely or partially underground. It can be work with water and drainage pipes, district heating pipes, installation pipes or earth reinforcement among others.

Pipe laying can imply that people completely or partly carry out the work in or around pipes, which can be very dangerous. The work can

• be cramped
• imply a risk of collapse
• imply a risk of not having air in order to breathe, or that the air is contaminated.

In this type of work different machines are often used that can entail risks

• during hoisting
• during drilling
• with leakage of chemicals or compressed air.

The works requires very thorough planning and identifying what types of risks that the working methods and machines can entail for the employees, both individually and together.

Today, material and technical aids are developed within this working area. Eventually it could minimize manual work in and around pipes. It is therefore important to early investigate possibilities and work in accordance with the following in the Work Environment Act: ’take into consideration the nature of the work and the technical and social development in the society.’

The designers´ choice of methods and techniques are examples of prerequisites that are given for the work. Unacceptable working conditions have been found in connection with replacement of old water pipes and fatal accidents have occurred in connection with work in district heating pipes.

The Swedish Work Environment Authority´s provisions about rock work and mining work includes risks and preventive measures against ill-health and accidents, for example suitable working methods, equipment, ventilation and evacuation. These provisions are only available in Swedish:

Berg- och gruvarbete (AFS 2010:1), föreskrifter

The provisions about chemical hazards specify demands for workplaces with chemical risks:

Chemical Hazards in the Working Environment (AFS 2019:9Eng), provisions