Page 10 - OHS, July/August 2022

CONFINED SPACES
Why Specific PPE is Needed for Safe Entry and Exit
Understanding the risks associated with a confined space entry can better prepare entrants and supervisors when selecting PPE.
CBY ANNE OSBOURN
onfined 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 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 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.
Fall Protection
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 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 emergencies with extremely tight openings, a spreader bar can provide both comfort and security when lowering and lifting workers.
Gas Detection
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.
10 Occupational Health & Safety | JULY/AUGUST 2022
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