Key Considerations for Working in Confined Spaces

Confined spaces appear in all factories in one form or another. Sometimes we need to work in a confined space once a week, sometimes once a month, sometimes once a year, but the real issue is not the frequency—it is whether we can access the space, work within it, and perform a rescue if an undesired situation occurs. For all of this to be possible, the risk assessment and emergency action plan must be correct, sufficient, and practical. Work in confined spaces should generally follow 4 steps. 1- Planning: Risk assessment and emergency action plan, 2- Access, 3- Work inside, 4- Rescue. Before proceeding with these 4 steps, it is helpful to clarify the term "confined space." According to OSHA (Occupational Safety and Health Administration) in the United States, a confined space can be defined by three main questions. 1- Is it large enough and configured so that an employee can physically enter and perform an assigned job? 2- Is entry or exit limited or restricted? 3- Is it not designed for continuous occupancy? If you answer "Yes" to all three questions, then you must ask one more question. "Does the area to be worked contain serious health and safety hazards such as atmospheric hazards, suffocation, voids, etc.?" If you also answer "Yes" to this question, then the area where you work should be designated as a permit-required confined space.

Before any work is performed within a confined space, a risk analysis must definitely be conducted, and a practice drill must be carried out with the equipment to be used and before actual work, in order to test the use and operation of the equipment to be used.

For the second step, the access section, it is necessary to determine whether the area to be entered has horizontal or vertical access. Depending on this, different solutions can be considered for access and rescue purposes. In Turkish factories, a tripod is generally kept on standby in case of an emergency. However, it should not be forgotten that in the event of an emergency, setting up the tripod at the incident location will take time. For this reason, the tripod must be set up from the moment of entry into the area before an incident occurs. Another issue is that the tripod is not suitable for every area. For example, in a location where lateral access will be performed, setting up a tripod would not be the correct approach. Another consideration is that in order to set up the tripod in a balanced manner, the surface on which the tripod's legs rest must be a level floor. Finally, if a fall occurs and/or a situation arises where the worker loses consciousness and needs to be rescued, after the person is pulled up with the tripod, the rescuer must make a physical effort to bring the person to a safe area. However, as you can see in the pictures below, access and rescue can also be provided with different solutions. For example, in cases of vertical entries such as tank entries, 5-part systems (Figure 1), horizontal entry equipment that can be used in horizontal entries (Figure 2), or light and mobile systems that can be used for both vertical and horizontal entries (Figure 3, Figure 4), can be evaluated specially for each confined space entry and selected according to their suitability. Figure 1. 5-part Davit System Figure 2. Systems for horizontal entry Figure 3. Horizontal entry example Figure 4. Vertical entry example During access to the interior, following the selection of anchor points for entry, it is important to select a safety harness suitable for the work that the employee will remain continuously attached to. Adding a suspension apparatus (Figure 5) with D-rings at the shoulders that allows easier entry and exit into the interior will allow the person to be lowered and removed in an extra comfortable manner. In addition to the person's comfort, the selection of a harness suitable for the work the person will perform inside also affects safety. For example, during welding work, a hole caused by a spark on the harness resulting from welding sparks reduces the protection of the safety harness. For this reason, it is recommended to prefer products made with Nomex/Kevlar material suitable for welding work.

Figure 5. Suspension Apparatus

Following the selection of the safety harness and anchor point, in order to enable the person to work safely, winches and/or automatic fall arresters should be selected depending on the work area. Periodic maintenance is critical for the 3 groups mentioned above used for access and rescue in confined spaces. In general, although the shelf life of equipment containing textile materials is set at 10 years, periodic inspections determine the service life. For mechanical products (tripod, automatic fall arrester, etc.), there are no problems with use as long as they pass periodic inspection. However, the instructions of the manufacturing company should also be taken into account for all of these. Whether there are any atmospheric hazards in the area to be entered and whether the work to be performed (cleaning, painting, welding, etc.) creates an additional atmospheric hazard is also an issue that should be evaluated separately. Before entering, gas values at all levels of the interior environment should be read both at the entry level and at specified distances. Generally, before entering, pump-type gas measurement devices (Figure 6) are preferred to measure the chemicals in the levels. This allows safe interior measurements to be made even at depths of 5, 10, 15 meters, etc. However, one of the most important points at this stage is ensuring that gas measurement devices are calibrated and bump-tested correctly and on time. Following gas measurements, depending on risk analyses and the nature of the work to be performed inside, other necessary personal protective equipment should be put on and work should begin. However, one of the most frequently encountered problems is communicating with people using respiratory protection inside confined spaces. Because communication is generally provided by radio, but the voices of people wearing masks on their faces cannot be transmitted clearly through the radio. In such cases, with each area evaluated according to its own characteristics, it is recommended to use systems (Figure 7 and 8) that can transmit sound clearly to the radio through microphones in positive-pressure masks.

Figure 7. Connection via Bluetooth Figure 8. Connection via cable

  In the final stage, the rescue section, it is essential to follow the emergency action plan and have rescue teams ready with all their equipment. In confined space work, in addition to correct equipment, risk analysis, and emergency action plan, one of the most critical points is that workers and supervisors overseeing workers in confined spaces have received necessary training and have also conducted practice drills with the products they will use. Mirey Bonfil Technical Coordinator Occupational Safety Department 3M Türkiye