Microsoft Word - SOP - Hands-On Sessions

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Hands-On - PRV Replacement

STANDARD OPERATING PROCEDURE

NAME:

Operation, Isolation and Replacement of Pressure Relief Valves

SCOPE:

This procedure details the normal operation of the pressure relief valves and instructions for their safe replacement. Procedure may be performed without interrupting system operation when equipment has a dual relief valve assembly. The oil pots are only equipped with single relief valves and will need to be pumped-out before replacing their relief valves. See the SOP for oil pots for detailed pumpout procedures.

EQUIPMENT:

Affects all pressure relief valves connected to the ammonia refrigeration system.

OPERATOR REQUIREMENTS:

A minimum of one (1) trained refrigeration operator is required to perform this procedure. The training can be from on-the-job experience or classroom instruction.

PPE required:

tools/equipment required:

Have within reach: full face respirator equipped with NH 3 cartridges

lock-out/tag-out equipment pipe wrenches

Teflon® tape & paste water source nearby sulfur stick ammonia monitor

Wear: chemical resistant gloves Goggles & face shield—whenever opening any part of the system.

Technical Operating Specifications:

Dual pressure relief valves are installed on most ammonia vessels and major components to prevent over-pressurization of the associated equipment. The dual relief valves are installed on three-way isolation valves so each relief valve may be isolated and serviced separately, without pumping out the equipment. The stem on the three-way valve should be turned fully counter-clockwise so that only one relief valve (farthest from stem) will be in service. If any relief valve activates, it must be replaced. The second relief valve is just for back-up purposes and is only to be used until the primary valve (which relieved) can be replaced. Equipment with only a single relief valve must be pumped out according to instructions contained in the SOP for that equipment before relief valve can be replaced.

Procedure: Operation, Isolation and Replacement of Pressure Relief Valves Reviewed: 11/01/2023

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