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Interpretations regarding Process Safety Information
The following utility interpretations of the PSM Standard have been paraphrased and summarized for ease of reading and for space considerations in this article. The exact wording, including fuller explanations by OSHA made be found in the actual documents referenced.
Question: Are loop diagrams
expected as Process Safety Information?
Answer: It is anticipated that employers would include loop diagrams, flow charts and narrative descriptions of control and interlock systems in their compilations of written process safety information required by §1910.119(d) before they conduct any process hazard analyses. (OSHA letter of September 21, 1992)
Question: When are material and energy balances required for new processes?
Answer: If a new line, unit, or "train" is added to supplement the process, these could be considered new processes requiring material and energy balances. If the increase in capacity is accomplished through new or different chemistry, such as a chemical reaction in place of a unit physical operation, this would be a new process requiring the material and energy balance calculation. If the capacity increase is due to process changes made to existing equipment and/or chemistry, such as increase/decrease in flows, temperatures, pressures etc., or efficiency gains, these modifications would not constitute a new process, and would not be required to have a material and energy balance. These modified processes would be subject to all of the PSM requirements including Management of Change, and Pre- startup safety review, paragraphs §1910.119(l) & (i), respectively. (OSHA letter of September 25, 1995)
Question: Is a previous edition of a current code or standard (i.e. 1972 edition of the Section VIII of the ASME Code) considered to be "a code or standard no longer in general use"?
Answer: Yes. This question is generated from OSHA's standard 29 CFR 1910.119(d)(3)(iii). The intent of this requirement is for the employer to determine and document that PSM covered equipment which was designed and constructed to codes, standards or practices which are no longer in general use can continue to operate in a safe manner. After the employer makes the determination required by the standard, it will be the basis for the decision to take the equipment out-of-service or to continue operations. If the equipment is to be kept in-service, the determination will be the baseline from which all future operation, inspection, testing and maintenance is conducted. In making the determination the standard requires the employer to evaluate the design, maintenance, inspection, testing and operation of the PSM covered equipment. When making the determination required by the standard, OSHA intends that the employer document that PSM covered equipment is consistent with the latest editions of codes and standards. If an employer determines that covered equipment is not in conformance with the latest editions of codes, standards or practices, the employer must document which codes and standards were used and that the design, construction, maintenance, inspection, testing and operation are still suitable for the intended use. (OSHA Letter of March 5, 1998)
Question: Given a pressure vessel designed, constructed, inspected and Code-stamped in accordance with a previous edition of the ASME Code, and for which a manufacturers U-1 form exists, is it necessary to recalculate the vessel's design characteristics (wall thickness, nozzle reinforcement, etc.)?
Answer: If the original design and construction is in accordance with the latest edition of design and construction codes and standards for equipment covered by the PSM standard, then OSHA's standard 1910.119(d)(3)(iii) does not require the employer to recalculate design characteristics of PSM covered equipment. However, if there are differences between the original and the latest edition of design and construction codes and standards, then OSHA requires the employer to document those differences. The employer must also show how those differences are consistent with the latest editions of design and construction codes and standards to assure that the equipment can continue to function in a safe manner. A pressure vessel designed and constructed using any edition of the ASME Code and which posssses [sic] a manufacturers' U-1 certification, may have had a change in-service at sometime during its operating history. To assure safe operation the employer when making its determination as required by this standard must also determine and document that the in-service operation, inspection, testing and maintenance of PSM covered equipment considers the change in-service and its impact is consistent with the latest codes, standards and practices so as to assure safe operation. (OSHA Letter of March 5, 1998)
Question: When performing recalculation as a means of establishing suitability for intended service, and given a pressure vessel for which no documentation of material of construction, welding procedures or radiographic testing exists, is it acceptable to assume the lowest value for these variables (i.e. lowest weld joint efficiency factor, lowest allowable stress value for the class of materials involved, etc.) and to incorporate these values into the recalculation?
Answer: When an employer conducts an engineering analysis, including recalculation, when no documentation exists for the material of construction, welding procedures or radiographic testing, it is appropriate to assume the lowest value for the listed variables in the engineering analysis as a means of determining that the in-service condition of covered equipment is appropriate for its intended use. The engineering analysis must be conducted in conformance with the latest editions of codes and standards. (OSHA Letter of March 5, 1998)
Question: Are there any General Industry standards that require an employer to compile, use and maintain current electrical hazardous area classification drawing(s) for facilities containing flammable or combustible materials?
Answer: Paragraph 1910.307 Hazardous (classified) locations which applies to workplace electrical utilization installations, does not specifically require an employer to compile, use, or maintain current, electrical hazardous area classification drawing. When applicable however, electrical classification information pertaining to process equipment may be required under paragraph 1910.119(d)(3)(i)(C). Please note that paragraph 1910.119(d) requires that process safety information be compiled by the employer. However, the method used to compile this information is not specified. This is consistence with the performance-oriented intent of the §1910.119 Process Safety Management Standard. An employer may choose to compile electrical classification information on drawings specifically dedicated for that purpose or by annotations to existing plans or drawings and by other methods or combination of methods including tables, or written commentary.
Question: If an employer prepares electrical hazardous area classification drawings and issues them to employees with the intent of using them to consider the classification of an area (whether required by OSHA per question 1 or not), must the drawings: accurately represent the hazards involved, be updated to reflect process flammable or combustible material hazards and if required, is there a specific updating time limit?
Answer: An employer must maintain electrical hazardous area classification drawings current for use (to provide for the safety) of his or her employees. (OSHA letter of December 12, 1997)
More information about the old processes
and retention of Process Safety inforamtion:
- Old/used equipment: Analysis and/or testing appropriate to the new service with revised documentation of PSI is required. (OSHA Instruction CPL 2-2.45A CH-1 – PSM Compliance Directive)
- An old Plant with missing PSI: The company must obtain or generate the PSI. This may be delayed to coincide with the PHA schedule, except where a PSSR is required, in which case the modified PSI must be in place prior to startup. (OSHA Instruction CPL 2-2.45A CH-1 – PSM Compliance Directive)
- PSI Retention: Up-to-date (emphasis added) PSI must be kept for life of process (OSHA Instruction CPL 2-2.45A CH-1 – PSM Compliance Directive)
Although verbal interpretations have no official standing and federal employees rarely speak for attribution, there have been a number forums following the adoption of the PSM Standard where OSHA representatives have made themselves available to speak about PSM and answer questions. These verbal interpretations contain some interesting information on OSHA’s thinking (or at least the thinking of the person answering the question). Also, OSHA has published non-mandatory guidance on PSM issues in OSHA Publication 3133 (the “purple booklet”). This guidance is also unofficial. The following verbal clarifications and other non-mandatory guidance of the PSI element of the PSM Standard has been issued:
- PSVs are critical and information that supports PSV design and specification is critical - simple data sheets are not enough, calculations or other detailed documents will be required (emphasis added) (OSHA co-sponsored PSM workshops in Spring, 1993, OSHA Region VI presentations on PSM in January, 1994)Generic design basis documentation - Design basis for one system cannot be inferred from the documents of a like system (OSHA Region VI presentations on PSM in January, 1994)
- A PSM manual or central file is not required. (OSHA Region VI presentations on PSM in January, 1994)Electronic data management of PSI is acceptable and superior, if hard copies are/can be generated when needed if computer fails frequently
(OSHA Region VI presentations on PSM in January, 1994)
- Electronic signatures are acceptable
(OSHA Region VI presentations on PSM in January, 1994)
To see a specific letter or other interpretive document published by OSHA, visit OSHA’s website at
http://www.osha-slc.gov/OshDoc/toc_interps.html. As a service to our clients and readers,
AcuTech has included many of these documents, including the letters of interpretation discussed above, in a continuous Word® file. This file allows for easier searching for keywords that might be of interest and makes it easier to determine if an interpretative document has been published on a particular topic or if any of them address a specific PSM-related issue. This file may be found at
http://www.acusafe.com/psm/process-safety-management-interp_letters.html
In the next several issues of the AcuSafe newsletter, we will include a discussion of interpretations related to regulations that are referenced by the PSM Standard but pre-existed when the PSM Standard became effective. These apply to the Hot Work Permits and Emergency Response elements of
PSM.
If you have an interpretation that you would like to share with AcuSafe or
feedback about this feature, please email us at editor@acusafe.com.
To go back to the OSHA Interpretations Feature Index, click here
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