NFPA 56-2020 Standard for Fire and Explosion Prevention During Cleaning and Purging of Flammable Gas Piping Systems.
4.4.2 Stand-Down. If the conditions during the purging or cleaning activity deviate from those indicated in the written procedure, resulting in a safety hazard, the purging or cleaning activity shall be discontinued according to the stand-down instructions. 4.5* Safety Validation. A written safety validation shall be performed for cleaning and purging procedures. 4.5.1* The safety validation shall be conducted independently after the procedure has been written and shall evaluate hazards, errors, and malfunctions related to each step in the procedure to validate the measures prescribed in the proce‐ dure or make recommendations for additional hazard mitiga‐ tion measures if necessary. 4.5.2* Recommendations (also called “action items”) result‐ ing from the safety validation shall be resolved prior to the activity being conducted. 4.5.3* Prior to initiation of a cleaning or purging activity, the safety validation shall be approved by a designated individual who is competent and knowledgeable in the procedure and hazards and who is authorized to provide such approval. 4.6* Management of Change. Written procedures to manage change to process materials, technology, equipment, proce‐ dures, and facilities shall be established and implemented.
4.6.1 The management-of-change procedures shall ensure that the following issues are addressed prior to any change: (1) The technical basis for the proposed change (2) The safety and health implications (3) Whether the change is permanent or temporary (4) Modifcations to cleaning and purging procedures (5) Employee training requirements (6) Authorization requirements for the proposed change 4.6.2* Implementation of the management-of-change proce‐ dures shall not be required for replacements-in-kind. 4.6.3 The written cleaning and purging procedure, as required by Section 4.4, shall be updated to incorporate the change. 4.7 Documentation. 4.7.1 Cleaning and purging procedures shall be documented and available at the job site. 4.7.2 The safety validation documentation shall include the following items: (1) Names, company names, and addresses of the primary developer and other principal team members responsible for the safety validation (2) Name(s), company name, and address of the principal operational personnel representing the plant owner or operator (3) Date of preparation and any applicable modifcation dates (4) The completed safety validation in accordance with Section 4.5 (5) Any procedures related to the safety validation and any limiting conditions identifed in the management-of- change assessment required by Section 4.6.
NFPA 56 pdf download.