Wisconsin Administrative Code › Department of Safety and Professional Services › SPS 301-399 - Safety, Buildings, and Environment › SPS 326-360 - General, Part II › Chapter SPS 340 - Gas systems › Subchapter V - Liquefied Petroleum Gas Systems › Section SPS 340.52 - Amendments to NFPA standards

Current through June 24, 2024
(1) PURGING
					 REQUIREMENTS. Substitute the following wording for the requirements in NFPA 54
					 sections 8.3.1 to 8.3.4:
(a)
General.
The purging of all piping, appliances and equipment
					 that exist on or after September 1, 2011, shall be in accordance with this
					 subsection.
(b)
Piping
					 systems required to be purged outdoors.
1. `Application.' The purging of piping
					 systems shall be in accordance with subds. 2. to 5. where the piping system
					 meets either of the following:
a. The design
					 operating gas pressure is greater than 2 psi.
b. The piping being purged contains one or
					 more sections of pipe or tubing greater than 2 inches in diameter and having
					 the lengths in Table 340.52.
2. `Removal from service.' Where existing gas
					 piping is opened, the section that is opened shall be isolated from the gas
					 supply and the line pressure vented in accordance with subd. 4. Where gas
					 piping meeting the criteria of Table 340.52 is removed from service, the
					 residual fuel gas in the piping shall be displaced with an inert gas.
Nominal Pipe Size (in.)
Length of Piping (ft.)
2
%
> 50
3
> 30
4
> 15
6
> 10
8 or larger
Any length
3. `Placing in operation.' Where gas piping
					 containing air and meeting the criteria of Table 340.52 is placed in operation,
					 the air in the piping shall first be displaced with an inert gas. The inert gas
					 shall then be displaced with fuel gas in accordance with subd. 4.
4. `Outdoor discharge of purged gases.' The
					 open end of a piping system being pressure vented or purged shall discharge
					 directly to an outdoor location. Purging operations shall comply with all of
					 the following requirements:
a. The point of
					 discharge shall be controlled with a shutoff valve.
b. The point of discharge shall be located at
					 least 10 feet from sources of ignition, at least 10 feet from building openings
					 and at least 25 feet from mechanical air-intake openings.
c. During discharge, the open point of
					 discharge shall be continuously attended and monitored with a combustible gas
					 indicator that complies with subd. 5.
d. Purging operations introducing fuel gas
					 shall be stopped when 90% fuel gas by volume is detected within the
					 pipe.
e. Persons not involved in
					 the purging operations shall be evacuated from all areas within 10 feet of the
					 point of discharge.
5.
					 `Combustible gas indicator.' The combustible gas indicator used during purging
					 operations shall be listed and shall be calibrated in accordance with the
					 manufacturer's instructions and recommended schedule. The combustible gas
					 indicator used for pipe discharge monitoring shall numerically display a volume
					 scale from 0% to 100% with a resolution of not greater than 1%
					 increments.
(c)
Piping systems allowed to be purged indoors or outdoors.
1. `Application.' The purging of piping
					 systems shall be in accordance with subd. 2 where the piping system meets both
					 of the following:
a. The design operating
					 pressure is 2 psi or less.
b. The
					 piping system being purged is constructed entirely from pipe or tubing of
					 2-inch nominal size or smaller, or larger pipe or tubing with lengths shorter
					 than specified in Table 340.52.
2. `Purging procedure.' The piping system
					 shall be purged in accordance with one or more of the following:
a. The piping shall be purged with fuel gas
					 and shall discharge to the outdoors.
b. The piping shall be purged with fuel gas
					 and shall discharge to the indoors or outdoors through an appliance burner not
					 located in a combustion chamber. The burner shall be provided with a continuous
					 source of ignition.
c. The piping
					 shall be purged with fuel gas and shall discharge to the indoors or outdoors
					 through a burner that has a continuous source of ignition and that is designed
					 for such purpose.
d. The piping
					 shall be purged with fuel gas that is discharged to the indoors or outdoors,
					 and the point of discharge shall be monitored with a listed combustible gas
					 detector in accordance with subd. 3. Purging shall be stopped when fuel gas is
					 detected.
e. The piping shall be
					 purged by the gas supplier in accordance with written procedures.
3. `Combustible Gas Detector.' The
					 combustible gas detector used during purging operations shall be listed and
					 shall be calibrated or tested in accordance with the manufacturer's
					 instructions and recommended schedule. The combustible gas detector used for
					 pipe discharge monitoring shall indicate the presence of fuel gas.
(d)
Purging appliances and
					 equipment.
After the piping system has been placed in operation,
					 appliances and equipment shall be purged before being placed into operation.
Note:
See Appendix for further information
						relating to purging.