Engineering ToolBox - Resources, Tools and Basic Information for Engineering and Design of Technical Applications!

This is an AMP page - Open full page! for all features.

• the most efficient way to navigate the Engineering ToolBox!

# Sanitary Drainage Systems - Volume Flow

The theoretical total load for a sanitary drainage system can be calculated by adding loads for every fixture in the system. Due to intermittent use of the fixtures - this method in general adds up to unrealistic high values for the main drainage lines.

• realistic - or expected - total load is always lower than theoretical total load

Expected total load for sanitary drainage systems should instead be estimated by using empirical equations like

qet = k ( Σqn )1/2                                (1)

where

qet = expected total drainage load (gpm, l/s)

k = system coefficient describing the nature of the system

Σqn = total theoretical load - all fixtures summarized (gpm, l/s)

Note that the minimum expected total load can never be less than the load from the largest fixture.

The system coefficient compensates for the nature of the system. For systems serving large groups of people where the use is intermittent, like

• hotels
• hospitals
• schools
• theaters
• wardrobes in factories
• etc

the coefficient - k - should be in the range 0.5 - 0.8. Closer to 0.8 for smaller systems with fewer fixtures and closer to 0.5 for larger systems with many fixtures.

For more ordinary systems where consumption patterns are more continuously, like

• homes
• offices
• nursing homes

the coefficient - k - should be in the range 0.3 - 0.6. Closer to 0.3 for larger systems with many fixtures and closer to 0.6 for smaller systems with few fixtures.

### Example - Sanitary Drainage System Hospital

If the theoretical total load from fixtures in a smaller hospital adds up to 50 l/s - the expected total load can be estimated to

qet = 0.7 (50 l/s)1/2

= 4.9 l/s

Assuming this is a smaller hospital the coefficient is set to 0.7.

## Related Topics

### • 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.

### ASTM D2729 - Poly(Vinyl Chloride) (PVC) Sewer Pipe - Dimensions

Dimensions of Poly(Vinyl Chloride) (PVC) Sewer Pipes with belled end.

### Cast Iron Soil Pipes - Dimensions

Dimensions of cast iron soil pipes.

### Cleanouts in Draining Systems

Cleanouts provides access to the sewer for rodding.

### DFU - Drainage Fixture Units

DFU are used to calculate the drainage flow from fixtures and the required capacities of sewer service systems.

### Drain Pipes and Vent Stacks

Drain pipes and vent stack sizing.

### Drain Waste and Vent Pipes - Hanger Spacing

Support of Drain Waste and Vent - DWV - pipes.

### 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.

### Sanitary Piping - Drainage Fixtures Unit Loads

Maximum Drainage Fixture Unit - DFU - loads in sanitary piping systems.

### Septic Systems

Septic systems handles waste from drain 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.

## Search Engineering ToolBox

• the most efficient way to navigate the Engineering ToolBox!

## SketchUp Extension - Online 3D modeling!

Add standard and customized parametric components - like flange beams, lumbers, piping, stairs and more - to your Sketchup model with the Engineering ToolBox - SketchUp Extension - enabled for use with the amazing, fun and free SketchUp Make and SketchUp Pro . Add the Engineering ToolBox extension to your SketchUp from the Sketchup Extension Warehouse!

## Privacy

We don't collect information from our users. Only emails and answers are saved in our archive. Cookies are only used in the browser to improve user experience.

Some of our calculators and applications let you save application data to your local computer. These applications will - due to browser restrictions - send data between your browser and our server. We don't save this data.