Enclosed space means a space that has limited entry and exit openings, and there is also insufficient natural ventilation in it. It is not a space prepared for the constant presence of employees in it. For this reason, working in confined spaces as well as tanks is a particularly dangerous job.

The main hazards associated with the employee’s stay in a confined space include: high risk of fire or explosion, loss of consciousness due to the accumulation of dangerous gases heavier than air such as: carbon dioxide, methane or hydrogen sulfide, drowning caused by increased water levels in a confined space, fainting due to low oxygen content in wells, septic tanks, canals or wells, suffocation caused by loose backfilling  material or inability to get outside.

Performing work in tanks, ducts, interiors of technical devices and in other dangerous confined spaces is regulated by regulations.

Basic rules for undertaking work in tanks:

• Taking up and conducting work in tanks may take place only on the basis of a written permit issued in the manner determined by the employer,
• The work should take place under constant supervision, and the person giving the order to perform it is obliged to check whether the organization and technical conditions ensure the safety of employees;
• Provision should be made for immediate first aid in the event of an emergency or accident to a worker in an enclosed space.

Before employees start working in the tank, the employer is obliged to inform them about the scope of work they are to perform, the type of threats that may occur, the necessary collective and individual protection measures and the manner of their application, the method of signaling between those working inside it and those who protect them outside, how to act in the event of an emergency.

Before starting work in the tank, the worker or workers must be provided with belaying by at least one person remaining on the surface. The belaying person should be in constant contact with the workers inside the tank and be able to extract them and, in the event of an emergency, immediately notify other persons who can, if necessary, provide assistance.

Workplace preparation

• the tank must be emptied and pre-cleaned by washing, blowing with steam or inert gas and blowing with air;
• Blowing the tank with oxygen is unacceptable due to the possibility of an explosive mixture with methane or hydrogen sulfide;
• if work in the tank may be associated with a fire hazard, the necessary fire protection measures must be used;
• it is necessary to disconnect the supply to the tank of materials, substances and refrigerants from other tanks, pipes, apparatus, etc.;
• radiators, mobile devices and other devices which may pose a risk inside the tank must be disconnected from the power sources;
• during operation in the tank, railway tracks, switches, conveyors, chute places, etc., located above the tank, must be excluded from traffic or immobilized;
• Immediately before commencing operation inside the tank, the air in the tank must be tested for oxygen and gases and vapours of substances classified as dangerous;
• the air temperature in the tank should not differ from the ambient temperature by more than 5°C;
• whereas the necessary collective and individual protection measures must be provided;

Organization of work

• Whereas, in order to maintain adequate air parameters inside the tank, all the handles should be left open while workers are in a confined space and, if this solution is not sufficiently effective, mechanical air blowing should be used;
• if the lighting is insufficient, the inside of the tank shall be illuminated using an electric light source with a safe voltage;
• the transport of tools, other objects and materials inside the tank should be carried out in a way that does not pose any risks or nuisances to the persons working there;
• if the tank contains liquid materials (wells) or loose materials (silos) in which it is possible to drown or fill the employee (regardless of the protection of appropriate personal protective equipment) – the employee should be lowered inside on a platform or other device enabling safe work;
• if explosive concentrations are possible in the tank, explosion prevention measures must be used.

A worker entering the tank should be equipped with appropriate personal protective equipment, in particular: safety harnesses with a rope attached to a sufficiently durable element of the external structure; helmet and protective clothing; full respiratory protection (depending on the composition of the air in the tank).

Source: https://asystentbhp.pl/prace-w-przestrzeniach-zamknietych/

Projekt otrzymał dofinansowanie z Norwegii poprzez Fundusze Norweskie 2014-2021, w ramach programu „Dialog społeczny – godna praca”.