Drain Pipes and Vent Stacks
Vents transports sewer gas through the building to open air space. Properly installed the vents prevents traps siphoning and sewage gas to leak into the interior building.
Different codes in different jurisdictions exists and must be adhered to locally. In general we talk about
- individual vents
- relief vents
- circuit vents
- branch vents
- stack vents
Individual vents
Individual vents serve individual fixtures.
This vents only one fixture but may connect into an other vent that extends to open air.
- an individual vent should be at least one-half the size of the drain it vents (no less than 1 1/4", 32 mm)
Relief vents
Relief vents provide additional air to the drainage system where the primary vent is too far from the fixture.
- an relief vent should be at least one-half the size of the drain it vents (no less than 1 1/4", 32 mm)
Circuit vents
Circuit vents are used with more than one fixtures. A circuit vent is installed before the last fixture extend up to open air or connects to an other vent that extend to the outside
- an circuit vent should be at least one-half the size of the drain it vents (no less than 1 1/4", 32 mm)
Branch vents
Branch vents are vents extending horizontally that connects multiple vents together.
Stack vents
A vent stack is used only for the purpose of venting.
Vents are normally sized by using the "Developed Length" (total linear footage of pipe making up the vent) method.
Maximum length of vent stacks and relief vents
| Size of Soil Waste Stack (in) | Length | |||||||
|---|---|---|---|---|---|---|---|---|
| Fixture Units Connected | Diameter of Required Vent Stack (in) | |||||||
| 1 1/4 | 1 1/2 | 2 | 2 1/2 | 3 | 4 | 5 | ||
| 1 1/4 | 2 | 30 | ||||||
| 1 1/2 | 8 | 50 | 150 | |||||
| 10 | 30 | 100 | ||||||
| 2 | 12 | 30 | 75 | 200 | ||||
| 20 | 26 | 50 | 150 | |||||
| 2 1/2 | 42 | 30 | 100 | 300 | ||||
| 3 |
10 | 30 | 100 | 200 | 600 | |||
| 30 | 60 | 200 | 500 | |||||
| 60 | 50 | 80 | 400 | |||||
| 4 |
100 | 35 | 100 | 260 | 1000 | |||
| 200 | 30 | 90 | 250 | 900 | ||||
| 500 | 20 | 70 | 180 | 700 | ||||
| 5 |
200 | 35 | 80 | 350 | 1000 | |||
| 500 | 30 | 70 | 300 | 900 | ||||
| 1100 | 20 | 50 | 200 | 700 | ||||
Drainage and Vent Pipes
Materials used in drainage an vent pipes according US standards.
| Piping Material | US Standards |
|---|---|
| Acrylonitrile butadiene styrene (ABS) plastic pipe in IPS diameters, including Schedule 40, DR 22 (PS 200) and DR 24 (PS 140); with a solid, cellular core or composite wall | ASTM D2661; ASTM F628;ASTM F1488; CSA B181.1 |
| Cast-iron pipe | ASTM A74; ASTM A888; CISPI 301 |
| Copper or copper-alloy pipe | ASTM B42; ASTM B43; ASTM B302 |
| Copper or copper-alloy tubing (Type K, L, M or DWV) | ASTM B75; ASTM B88;ASTM B251; ASTM B306 |
| Galvanized steel pipe | ASTM A53 |
| Glass pipe | ASTM C1053 |
| Polyolefin pipe | ASTM F1412; CSA B181.3 |
| Polyvinyl chloride (PVC) plastic pipe in IPS diameters, inclu-ing Schedule 40, DR 22 (PS 200), and DR 24 (PS 140); with a solid, cellular core or composite wall | ASTM D2665; ASTM F891; ASTM F1488; CSA B181.2 |
| Polyvinyl chloride (PVC) plastic pipe with a 3.25-inchO.D. and a solid, cellularcore or composite wall | ASTM D2949, ASTM F1488 |
| Polyvinylidene fluoride (PVDF) plastic pipe | ASTM F1673; CSA B181.3 |
| Stainless steel drainage systems, Types 304 and 316L | ASME A112.3.1 |
Related Topics
• Dimensions of Pipes and Tubes
Pipe, tube and fittings sizes and dimensions. Inside and outside diameters, weights and more.
• Sanitary Drainage Systems
The purpose of the sanitary drainage system is to remove effluent discharged from plumbing fixtures and other equipment.
Related Documents
ASTM B306 Copper Tubes for Drain, Waste and Vent - Dimensions and Working Pressures
Dimensions of copper tubes ASTM B306 Drain Waste and Vent - DWV.
Cleanouts in Draining Systems
Cleanouts provides access to the sewer for rodding.
Draining Systems - Main Vents
Vents in draining systems protects traps against pressure differences that could cause them to siphon or blow out .
Drains and Sewers - Capacities vs. Size
Drainage Fixture Units (DFU) connected to building drains and sewers.
Fixtures Trap Sizes
Recommended drain trap sizes for different types of fixtures
Plumbing Codes
Plumbing or sanitation codes are a set of rules and regulations imposed by cities, counties or states.
Sanitary Drainage Systems - Volume Flow
Calculate expected volume flow load in sanitary drainage systems.
Sanitary Piping - Drainage Fixtures Unit Loads
Maximum Drainage Fixture Unit - DFU - loads in sanitary piping systems.
Sewer Pipes - Capacities vs. Slope
Carrying capacities of sewer and wastewater pipes - gpm and liter per second.
Waste Water Piping - Flow Capacities vs. Dimensions
In sewage piping and pumping systems the fluid flow rate must be kept within certain limits to avoid operating problems.