Minnesota Administrative Rules

4715.2520 VENT STACKS AND STACK VENTS.

Subpart 1.

Vent stack required.

For each sanitary building sewer, at least one three-inch vent stack (or stack vent) carried full size through the roof shall be installed as provided in part 4715.2330. A vent stack or main vent shall be installed with a soil or waste stack whenever individual vents, relief vents, or branch vents are required for stacks of three or more branch intervals.

Subp. 2.

Connections at base and top.

For stacks of three or four branch intervals in height, all main vents or vent stacks shall connect full size at their base to the main soil or waste stack below, through, or not more than 18 inches above the lowest fixture branch.

For stacks of five or more branch intervals in height, a main vent or vent stack shall connect full size with the soil or waste stack it serves, with a wye and one-eighth bend below the lowest fixture branch connected to such soil or waste stack, or at a point approved by the administrative authority.

Each such soil or waste stack, and vent stack shall be similarly cross-connected with a yoke vent at intervals of not more than five branch intervals as described in part 4715.2640.

Subp. 3.

Offsets for stacks of five or more branch intervals or stories.

As provided in part 4715.2360, soil and waste stacks offset at an angle of more than 45 degrees from the vertical, that receive the discharge of fixtures four or more branch intervals or stories above the offset, shall have a yoke vent installed (as per part 4715.2640) at the base of the upper stack section.

Subp. 4.

Vent headers.

Where stack vents and vent stacks are connected into a vent header, such connections shall be made at the tops of the stacks. The vent header shall connect to a vent extension through the roof.

Subp. 5.

Size and lengths of vent stacks.

		DIAMETER OF VENT IN INCHES
SIZE OF SOIL OR WASTE STACK IN INCH- ES	FIX- TURE UNITS CON- NECT- ED in d. f. u.	1-1/4	1-1/2	2	2-1/2	3	4	5	6	8	10	12
		MAXIMUM DEVELOPED LENGTH OF VENT, IN FEET
1-1/4	2	50
1-1/2	4	40	200
2	9		100	200
2	18		50	150
2-1/2	42		30	100	300
3	72			50	80	400
4	240			40	70	250
4	500				50	180	700
5	540					150	600
5	1100					50	200	700
6	1900						50	200	700
8	2200							150	500
8	3600							60	250	800
10	3800								200	600
10	5600								60	250	800
12	6000									200	600
12	8400									100	300	900
15	10500									50	200	600
15	50000										75	180

Subp. 6.

Size and length of vents; individual, branch, circuit, and header.

		Diameter of Vent, in Inches
	1-1/4	1-1/2*	2	2-1/2	3	4	5	6
Fixture Units connected in d.f.u.		Maximum Developed Length of Vent, in Feet
2	50	ul
4	40	200	ul
8	np	150	250
10		100	200	ul
24		50	150	400	ul
42		30	100	300	500
72		np	50	80	400
240			np	50	200	ul
500				np	180	700	ul
1100					50	200	700

*Except 6 fixture unit fixtures.

ul -- Unlimited length.

np -- Not permitted.

Statutory Authority:

MS s 16B.59 to 16B.75; 326.37 to 326.45; 326B.101 to 326B.194; 326B.43 to 326B.49

History:

23 SR 686; 28 SR 146; L 2007 c 140 art 4 s 61; art 6 s 15; art 13 s 4; L 2008 c 337 s 64; 33 SR 2042

Published Electronically:

May 14, 2012