## Min. & Max. velocity flow for sewer pipes

## Min. & Max. velocity flow for sewer pipes

(OP)

I have been told by the city that I need to design sewer pipes flowing half full to have a minimum of 2 fps velocity.

Is this standard practice, or does anyone know what the min. & max flow velocities are for sewer pipes.

Sizes 8-15" inside diameter.

Thanks in advance for any help.

Is this standard practice, or does anyone know what the min. & max flow velocities are for sewer pipes.

Sizes 8-15" inside diameter.

Thanks in advance for any help.

## RE: Min. & Max. velocity flow for sewer pipes

Maximum velocity is not so standardized, in my experience. Somewhere around 10 ft/sec is common practice. Higher velocities lead to problems of water hammer, erosion, gas release (H2S), etc.

You might look at ASCE's Manual of Practice. No. 9 or the Ten State Standards as widely cited authorities.

good luck

## RE: Min. & Max. velocity flow for sewer pipes

## RE: Min. & Max. velocity flow for sewer pipes

Thanks

## RE: Min. & Max. velocity flow for sewer pipes

## RE: Min. & Max. velocity flow for sewer pipes

That is if you are ignoring inlet and outlet conditions - a dangerous practice...

## RE: Min. & Max. velocity flow for sewer pipes

In general, maximum mean velocities of 8 to 10 ft/sec at the design depth of flow will not damage the sewer.

However, high velocities in small pipe sewers and corresponding low depths of flow may allo larger objects, which at times enter all sanitary sewer systems to remain on the inverts, where they may become lodged so firmly that the next rush of wastewater will not detach the objects.

## RE: Min. & Max. velocity flow for sewer pipes

## RE: Min. & Max. velocity flow for sewer pipes

## RE: Min. & Max. velocity flow for sewer pipes

## RE: Min. & Max. velocity flow for sewer pipes