The PSM standard does not have a separate rule for temporary changes. Instead, they fall under the same management of change requirements as permanent ones. 29 CFR 1910.119(l)(2) requires your MOC procedures to address, before any change, the technical basis, the impact on safety and health, modifications to operating procedures, the necessary time period for the change, and authorization requirements. That "necessary time period" item is where temporary changes live. OSHA has issued very few letters of interpretation specifically about temporary changes, so this page relies on the standard itself, OSHA's PSM compliance directive, and the closest related letters.

What OSHA Tells Its Inspectors

Sep 13, 1994 · Compliance directive
CPL 2-2.45A CH-1: what inspectors check in your MOC procedures
OSHA's PSM compliance directive tells compliance officers to review MOC procedures for, among other things, "requirements for reviewing designs for temporary and permanent changes," "time limit authorizations for temporary changes," and "steps required to return the process to status quo after temporary changes." It also directs them to confirm that procedures address the necessary time period for each change before it is made, under (l)(2)(iv). This is not a letter of interpretation, but it is OSHA's own enforcement guidance on what a compliant MOC program looks like.
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Related OSHA Letters

Oct 31, 1996
MOC applies broadly, except replacement in kind
OSHA confirmed that, except for replacements in kind, the MOC provisions apply even to changes in maintenance procedures and in equipment test and inspection frequencies, stressing the need to "thoroughly evaluate any contemplated changes to a process." Nothing in the standard exempts a change because it is short-lived.
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Jul 12, 2006
How long MOC records must be kept
OSHA explained that MOCs for chemicals or equipment become part of process safety information and must be kept for the life of the process, while MOCs for procedure changes may be retained until the next PHA revalidation. OSHA also expects enough MOC records to be available for the next compliance audit to review a representative sample.
Read OSHA Letter ↗

⚡ Key Compliance Takeaway

Treat a temporary change exactly like a permanent one, plus two extra controls: a defined time limit approved up front, and a documented plan to return the process to its original condition or convert the change through a new MOC. Those are the items OSHA's own directive tells inspectors to look for. Bypasses and jumpers left in place past their authorized time are the classic way a temporary change becomes an unreviewed permanent one.