# Vacuum Pumps - Exhaust Pipe Capacities

## Capacities of vacuum pump exhaust pipes.

The diagrams below can be used to indicate vacuum pump exhaust pipe line capacity:

### Air flow - *scfm*

### Air flow - *nl/s*

### Example - Vacuum Pump Exhaust Pipe

The exhaust air flow from a vacuum pump is *1200 cfm* and the required length of the exhaust piping is *60 ft*.

As we can see the range of the diagram above is limited but with half the flow - *600 cfm* - the maximum length of a *6"* pipe is approximately *120 ft*. Or in other words - with two *6"* pipes in parallel there will be enough capacity.

Alternatively - if we compare an *8"* pipe with a *6"* pipe - we see that the internal area of the *8"* pipe is twice the area of the *6"* pipe - and we can assume that a single *8"* pipe provides enough capacity.