NR 440.62(3)(e)3.3. In situ-sampling systems and sampling systems without purges are exempt from subds. 1. and 2. NR 440.62(3)(f)1.a.a. Each open-ended valve or line shall be equipped with a cap, blind flange, plug, or a second valve, except as provided in par. (a) 3. NR 440.62(3)(f)1.b.b. The cap, blind flange, plug, or second valve shall seal the open end at all times except during operations requiring process fluid flow through the open-ended valve or line. NR 440.62(3)(f)2.2. Each open-ended valve or line equipped with a second valve shall be operated with a second valve shall be operated in a manner such that the valve on the process fluid end is closed before the second valve is closed. NR 440.62(3)(f)3.3. When a double block-and-bleed system is being used, the bleed valve or line may remain open during operations that require venting the line between the block valves but shall comply with subd. 1. at all other times. NR 440.62(3)(f)4.4. Open-ended valves or lines in an emergency shutdown system which are designed to open automatically in the event of a process upset are exempt from the requirements of subds. 1. to 3. NR 440.62(3)(f)5.5. Open-ended valves or lines containing materials which would autocatalytically polymerize or would present an explosion, serious overpressure or other safety hazard if capped or equipped with a double block and bleed system as specified in subds. 1. to 3. are exempt from the requirements of subds. 1. to 3. NR 440.62(3)(g)(g) Valves in gas/vapor service and in light liquid service. NR 440.62(3)(g)2.2. In an instrument reading of 10,000 ppm or greater is measured a leak is detected. NR 440.62(3)(g)3.a.a. Any valve for which a leak is not detected for 2 successive months may be monitored the first month of every quarter, beginning with the next quarter, until a leak is detected. NR 440.62(3)(g)3.b.b. If a leak is detected the valve shall be monitored monthly until a leak is not detected for 2 successive months. NR 440.62(3)(g)4.a.a. When a leak is detected it shall be repaired as soon as practicable, but no later than 15 calendar days after the leak is detected, except as provided in par. (i). NR 440.62(3)(g)4.b.b. A first attempt at repair shall be made no later than 5 calendar days after each leak is detected. NR 440.62(3)(g)5.5. First attempts at repair include, but are not limited to, the following best practices where practicable: NR 440.62(3)(g)6.6. Any valve that is designated as described in sub. (7) (e) 2. for no detectable emissions, as indicated by an instrument reading of less than 500 ppm above background, is exempt from the requirements of subd. 1. if the valve: NR 440.62(3)(g)6.b.b. Is operated with emission less than 500 ppm above background as determined by the method specified in sub. (6) (c), and NR 440.62(3)(g)6.c.c. Is tested for compliance with subd. 6. b. initially upon designation, annually, and at other times requested by the department. NR 440.62(3)(g)7.7. Any valve that is designated as described in sub. (7) (f) 2. as a difficult-to-monitor valve is exempt from the requirements of subd. 1. if: NR 440.62(3)(g)7.a.a. The owner or operator of the valve demonstrates that the valve is unsafe to monitor because monitoring personnel would be exposed to an immediate danger as a consequence of complying with subd. 1., and