The PSM standard requires the employer’s PHA team to evaluate human factors during its process hazard analysis. CCPS defines human factors as “a common term given to the widely-recognized discipline of addressing interactions in the work environment between people, a facility, and its management systems.” The basic principle of assessing human factors is to determine whether the employer “fits the task and environment to the person rather than forcing the person to significantly adapt in order to perform their work.”
Very few PHA citations resulted from the PHA team completely omitting the human factors review. Instead, the majority of citations resulted from the PHA overlooking specific human factors issues. During inspections, OSHA found that some PHAs had failed to address:
■ Inadequate or unsafe accessibility to process controls during an emergency,
■ A lack of clear emergency exit routes, or
■ Inadequate or confusing labeling on equipment, procedures, and/ or P&IDs.
Specific examples include:
■ Inadequate alarm management, which required operators to perform multiple mental calculations and be aware of an unrealistic number of simultaneous alarms in a unit,
■ Requiring operation of a bypass valve that required crawling across a pipe rack, and
■ Locating emergency isolation valves where operators are in harm’s way during an emergency.
During the four (4) years of NEP inspections, OSHA also found that many refineries have over-relied on administrative controls to address human factors concerns. Over-reliance on administrative controls puts a burden on employees, invites confusion, and can increase the risk of failure-on-demand in an emergency.
Moreover, administrative controls may be inappropriate as the only protection against hazards with potentially severe consequences. Risk assessment and reduction techniques, such as a Layers of Protection Analysis, that utilize the hierarchy of controls can be effective in identifying the level and extent of safeguards necessary and appropriate to protect workers.
Source: https://www.osha.gov/sites/default/files/publications/OSHA3918.pdf