Confined spaces present health and safety risks for many workers, which is why recognizing and planning appropriately for working in confined spaces is so important. A confined space can be defined as an area that is large enough for an employee to physically enter and perform work, has limited or restricted means of entry or exit, and is not designed for continuous human occupancy.
Prior to commencing work in confined spaces, employers must carefully identify and assess the hazards in order to determine which precautions to take. For full compliance with OSHA standard governing confined spaces, 29 CFR 1910.146, it is necessary to rely upon the expertise of safety and health professionals such as industrial hygienists.
It is critical that procedures for confined space entry are followed and that necessary PPE is in use before any worker enters such areas, especially where there is a reasonably foreseeable risk of serious injury in entering or working in the confined space.
PPE for confined space work goes beyond simply one or two pieces of equipment. Confined space PPE spans fall protection, gas detection, respiratory protection and of course, head protection. But why does confined space PPE seem so complex? Here is a breakdown of the risks associated with PPE entry and exit, and why proper PPE is so important.
Confined space entry and retrieval equipment may be necessary to facilitate both entry into and exit from confined spaces. Proper retrieval systems for both workers and equipment consist of a full-body harness, tripod or davit systems and appropriate connecting devices.
Retrieval equipment is useful in lowering workers into confined spaces as it controls descent rate and prevents accidental falls into the work area. Additional work hoists are frequently used to raise and lower tools and equipment. Every entrant should always wear a full-body harness and have some sort of lifeline attached to the harness—even in horizontal entry applications. If an entrant becomes non-responsive, the lifeline can be used to haul the worker out as a non-entry rescue.
If a worker must be quickly extracted from a confined space without entrance of another worker into that confined space (non-entry rescue), lifting equipment employs concepts of physics to raise entrants out of work areas. Hoists typically have a mechanical advantage of 5:1. It is very difficult for an average person to pull someone out of a deep manhole without some mechanical advantage.
Tripods and davit arms should be equipped with two mechanical devices for confined space entry: a hoist for raising and lowering materials and personnel, and a self-retracting lanyard (SRL) with emergency rescue capability for back-up fall protection and emergency retrieval. The SRL with emergency rescuer remains connected to the confined space entrant. The SRL feature allows the entrant free movement within the confined space and doesn’t require a topside attendant to constantly payout/retract the cable line on a hoist as the entrant moves around. If the entrant needs to be rescued, the top-side attendant activates the emergency rescue feature of the SRL and retrieves the entrant without entering the confined space.
A wide variety of approved harnesses are available for use with retrieval equipment. Shoulder, back or chest D-rings/loops may be used as retrieval line attachment points. For confined space emergencies with extremely tight openings, a spreader bar is an ideal solution providing both comfort and security when lowering and lifting workers.
Hazardous atmospheres inside of a confined space are those which expose workers to risk of death, incapacitation, injury or acute illness from one or more of the following causes:
- Atmospheric oxygen concentration below 19.5 percent (oxygen deficiency). OSHA defines an oxygen-enriched atmosphere as that containing more than 23.5 percent oxygen by volume.
- Atmospheric concentration of any toxic contaminant above OSHA’s permissible exposure limit (PEL).
- Airborne combustible dust at a concentration that obscures vision at a distance of five feet or less.
- Immediately dangerous to life or health (IDLH) atmosphere which poses immediate threat of loss of life, may result in irreversible or immediate severe health effects and may result in eye damage, irritation or other conditions which could impair escape.
These risks make it critical to monitor air quality around you in real-time. Oxygen deficiency or enrichment conditions, as well as hazardous vapor and gas concentrations must be detected with reliable instrumentation.
While ventilation systems are frequently used to supply fresh air into a confined space in order to maintain conditions, these may not necessarily eliminate hazards. They can provide atmospheric stability within the space.
When choosing a portable or wearable gas detector, it’s important to consider not only durability, sensor technology and battery life, but also that device’s connectivity to cloud-based software solutions with fleet management and data collection capabilities. Having such data can create additional awareness around the devices and the workers using them so that safety programs can be adjusted quickly and proactively.
The hazardous atmospheres within confined spaces also make proper respiratory protection critical to helping keep workers protected in these environments.
Respiratory protection should be selected once confined space atmospheres have been analyzed and should be provided to all confined space entrants. Recommended confined space respirator types include: SCBA (self-contained breathing apparatus), dual-purpose SCBA, combination air-line respirators with escape cylinder, air-purifying respirators and escape respirators.
Because these devices vary in design, application and protective capability, it is important to first assess worksite contaminant levels as well as stay up-to-date with respiratory protection device limitations to help ensure you choose the right option for your needs. Some respirators may be used for various hazardous environments but if conditions reach IDLH levels or oxygen deficiency, only the highest levels of protection are required.
SCBAs provide the highest level of respiratory protection for confined space applications. SCBA are equipped with user-worn air cylinders that provide dependable, yet limited air supply without hoses or tethers to impede movement.
Major SCBA components include an air cylinder, low-pressure warning device, regulator, facepiece carrier and harness assembly. SCBAs are useful for confined space applications with entrances large enough to accommodate an entrant wearing the apparatus and cylinder; low-profile cylinders are available for tight confined space entrances. Under no circumstances should the entrant enter a confined space that contains a hazardous or potentially hazardous atmosphere unprotected and wait to have SCBA equipment lowered to him or her.
OSHA requires SCBA or combination pressure-demand airline respirators with escape cylinders for entry into IDLH environments. It must be noted that if using an airline respirator with escape cylinder, the user may not use the escape cylinder for entry and must be using the airline as the primary air source, since the cylinder is for escape only.
For both SCBA and combination airline apparatus, Grade D breathing air is regulated down from higher pressures to be delivered to the facepiece in response to breathing demand. Pressure demand respirators maintain a slight positive pressure to the facepiece at all times, which helps to prevent inward contaminant leakage.
In general, SCBAs are available in both low-pressure (either 2216 or 3000 psig) and high-pressure (4500 or 5500 psig) units. For a given cylinder size, high-pressure units have greater storage capacity, enabling longer service life. With high-pressure devices, SCBA users can select from 30-, 45- or 60-minute-rated cylinders. Thirty-minute-rated cylinders are used with low-pressure SCBA.
Head protection should be worn by all workers entering confined spaces. Type 1 helmets protect the wearer from top impact, while Type II helmets protect the wearer from top and lateral impact. The necessary protection should be determined by the employer based upon hazards within a specific work area. For confined spaces specifically, consider Type 1 hard hats with a low-profile design, allowing for improved range of motion during entry and exit.
Before entry into confined space work areas, all equipment should be inspected carefully before each use. Any equipment that shows any signs of wear, damage or doesn’t pass the inspection should not be used. Due to various risks and the number of different equipment that can be used, all personnel involved in confined space entry, including supervisors, entrants, attendants and rescue personnel, should be well trained. Individuals authorizing confined space entry must have complete knowledge of the space’s contents and hazards. All confined space workers must fully understand their duties prior to entry or if there are changes in assigned duties or confined space applications. An understanding of what defines a confined space and the necessary PPE for confined space work can help ensure worker safety during entry and exit.