Page 42 - Occupational Health & Safety, July/August 2019

CONFINED SPACES
The Complexities of Confined Space Safety
Once a space is designated a permit-required confined space, it engages an extra level of planning and preparation to mitigate the potential hazards. BY BAXTER BYRD
Confined spaces by any relative measure are complicated affairs. Few endeavors in- volving fall protection pose such dangers not only for the participant, but also those
tasked with monitoring the situation or performing rescues. Given the potential amount of personnel, equipment, and additional expertise a confined space operation may require, getting off on the right foot goes a long way to ensuring a safe environment for your workers.
To Permit or Not to Permit?
OSHA defines a confined space as an area that:
1. Is large enough for an employee to enter fully
and perform assigned work;
2. Is not designed for continuous occupancy by the
employee; and
3. Has a limited or restricted means of entry or exit. A confined space that fits this description is con-
sidered a non-permit-required work area. And al- though workers must take extra care when working in these spaces, the space itself poses no direct health risk to workers. When the conditions within the con- fined space do pose a direct health risk, OSHA consid- ers these areas to be permit-required confined spaces.
Like a non-permit-required confined space, there are certain identifiable traits of a permit-required con- fined space. OSHA identifies those as:
1. Contains or has the potential to contain a haz- ardous atmosphere;
2. Contains a material with the potential to engulf someone who enters the space;
3. Has an internal configuration that might cause an entrant to be trapped or asphyxiated by inwardly converging walls or by a floor that slopes downward and tapers to a smaller cross-section; and/or
4. Contains any other recognized serious safety or health hazards.
Once a space is designated a permit-required con- fined space, it engages an extra level of planning and preparation to mitigate the potential hazards.
The entry permit contains a comprehensive ac- counting of personnel, intended purpose of entry, means and methods of hazard abatement, rescue pro- cedures and contacts, and a host of other important information, including a specific duration of work. A confined space operation is not an open-ended af- fair, and an entry permit is valid for a specific amount of time only. If additional time is needed, the permit must be updated or a new permit must be issued. In addition, any time the confined space environment changes to something other than what is addressed on the permit, the permit must also be updated or a new permit issued.
Given the high degree of variability of conditions in a confined space, it is quite possible for the param- eters of a permit to change mid-work. Fluctuations in atmospheric oxygen are one such example where a permit may need to be updated.
The average atmospheric oxygen level is around 20.9 percent. If an inert gas, such as nitrogen, were introduced into a confined space and the oxygen level dropped below about 16 percent, workers would suf- fer hypoxia, which can cause accelerated heartbeat, nausea, poor judgment, and fatigue. Once the oxy- gen level dropped below 10 percent, workers would fall unconscious. If the oxygen level rose above 23.5 percent (perhaps due to a faulty shut-off valve some- where), the space would be considered oxygen rich, a condition that creates the potential for combustion. In a nutshell, altering a single factor (oxygen level) can shift the risk from one problem of unconsciousness and loss of motor skills to one of combustion. Because the remediation procedures for an oxygen-rich versus oxygen-depleted space are different, the permit must be updated to reflect the changed environment.
36 Occupational Health & Safety | JULY/AUGUST 2019
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