By John Baker, Total Safety Industrial Hygienist
Previously, Total Safety has emphasized the importance of including the need for IH resources during the planning of the turnaround to ensure that the exposure of employees (and possibly contractors) to airborne chemicals, silica, asbestos, noise, heat, radiation and other health hazards is monitored and controlled.
Pre-planning is essential for a successful turnaround because the specialized equipment and materials needed to test or detect certain materials and physical hazards may not be available on a moment’s notice. This is especially true for a chemical plant turnaround that may require testing for aldehydes, amines, cyanides or other chemicals not typically tested for in refinery turnarounds. Filter or sorbent media that are pre-treated with specific reagents are necessary to monitor for aldehydes, ketones and amines. Pesticide manufacturing plants typically require specialized testing and lab procedures to properly measure the materials of interest. Some materials, such as certain isocyanates, require the samples to be refrigerated and analyzed in the laboratory as soon as possible for accurate results. Polynuclear aromatic hydrocarbon air samples should be wrapped in foil and shipped refrigerated by overnight delivery to prevent degradation by sunlight and elevated temperatures. Testing for hexavalent chromium fumes while welding, cutting or arc gouging on stainless steel or high temperature alloys requires different filters and lab testing than for welding fumes on common steel. Chemicals that have high ionization energies, such as methanol or sulfur dioxide, may not be detected by a typical hand held or area photoionization detector, so a modified or different type of instrument would need to be used in that case.
Another point to be clarified well before the turnaround begins is the scope of work regarding confined space entry permits and hot work permits. Just because an IH technician is walking through a unit on the way to an assignment does not mean that he or she is under contract or allowed to “sniff” a space and “sign off” on a confined space or hot work permit. Generally, a supervisory employee of the owner or operator of the refinery or chemical plant is the person with the knowledge of the process and the equipment, and therefore, the associated hazards, who should be responsible for the final sign off on such permits. If this is not clarified at the planning stage, it could cause undue delays and confusion during the turnaround itself. The ventilation of confined spaces is another aspect of turnarounds that benefits from detailed prior planning. The location of the intake of the air supply must be in a clean, uncontaminated area, and the exhaust should likewise be directed away from workers, trailers or areas used for plant traffic. Be careful where “vac” trucks are discharging their exhaust as well.
Thought should also be given to which pre-turnaround activities need as much or more IH scrutiny than the maintenance, repair or replacement work itself. Some of the greatest potential for exposure occurs while units are being brought down and drained and purged. The potential for oxygen deficient atmospheres when nitrogen purging, or reactions of residues when using high temperature steam, should be considered and appropriate monitoring and PPE provided.
Thinking ahead and communicating in detail with the turnaround’s project engineering team about what, when, who and how of each work task will ensure that the IH resources committed to the turnaround are available when and where they are needed.
For additional information about pre-planning for your turnaround, contact us at 888.44.TOTAL.