Back Up Air Supply? Compressor is Down

High pressure accumulator tank bank....

Er, um, how is the original poster supposed to keep that lot charged to <...at least 80 psi...> while the <...main air compressor is down...>?

I have to agree. That looks to be about a 10 minute supply for a busy shop.

All of those tanks would amount to nothing more then a fart in the wind.

I had a 100 CFM Screw compressor @ 100 PSI... My highest demand tools was the DynaBrade Dynafile's that will consume 24-31 CFMs. These were the tools that required the highest air requirement demands.

Of course not all of them running constantly.

If It was a critical, or even important, compressor I'd just rent one until mine was back on-line.

A good temporary solution to an immediate problem as long as there is one readily available - at least it gets you going again in a relatively short period of time-don't forget to get a supply of the fuel required to run it. Been there, done that and at that point it time I plumbed in the necessary fittings and valves to do it again if necessary.

Wasn't long after my first main compressor down time that I reviewed my "critical" requirements and purchased and installed a backup unit. I didn't get fancy and have interconnections on the electrical with pressure sensors and the like (this can be done), but I made sure that there is always at least one knowledgeable person available to make the change over if the main does go down. Two switches, a few valves to open and a few to close and you are back up to pressure and flow rate that as needed to keep critical equipment up and running.

It depends on whether you just need to maintain static pressure (no flow), or maintain a minimum flow at a minimum pressure. In the first case, SE's idea of an accumulator would work. In my facility, we have a number of critical loads which must be maintained at a minimum pressure. These loads are all fed by one dedicated branch line from our main compressor. This branch can be isolated by a valve from the rest of the factory loads. This branch is also connected to an auxiliary compressor sized to handle the critical loads. The main compressor, which feeds the entire plant, is set to operate between 100 to 120 PSI. The auxiliary compressor is set to turn on at 80 PSI and off at 100 PSI.

one would also need to know what CFM requirements are

One would use (a) standby compressor(s) of some sort that would maintain <...at least 80 psi...> of the same throughput as the <...main air compressor...>, connected into the same apparatus downstream that would maintain the same levels of cleanliness and dryness of the compressed air as the <...main air compressor...>.

Maybe use the backup compressor?

If it's critical.. so is a backup.

80 psi can be had from a tire, but you need cfm... As stated

In my aquaculture days we needed to keep backup oxygen in case the oxygen generator broke down or was out for a service. We just had a quad of oxygen bottles linked to a manifold. Pretty sure you could do the same with air, say from scuba tanks or something like that.

My Ex-Wife may be available.. she was full of hot air.

In shops where the air supply is critical, you would have an installed backup compressor. In my home shop, I keep two smaller compressors. One will carry most loads and two will run the major equipment. One is portable and can backfeed into any quick connect in the system.

One company I worked at had three main compressors. Two would run at any one time and the third swapped in on a regular schedule. The running schedule was set up so that run time on each was balanced in the long run. PM was done on the down compressor and it was then available as backup to the system if anything went sideways with the other two compressors.

Three 50% compressors is an ideal solution. Switch them in and out to do PMs and oil changes. For the rare occasion when two machines are down, switch off the "non-critical" air loads and limp along on 50% capacity.

If "critical" base load is greater than 50%, you might use 60% or 75% as the compressor size. Alternatively, use four 33% machines or five 25% macchines to always have a spare, maintained machine ready to come on line.

If the compressor size is small, two 100% compressors is probably the more economical choice.