Rotary screw compressors
Shop-class 5 to 25 HP models with the sizing table and dryer pairings.
Size your shop compressor
Industry: Automotive and Body Shops
Compressed Air Systems for Automotive Manufacturing and Shops
- Since 1978
- Sullair dealer since 1984
- 14 locations
- under 2 hour response
Shop Air Spec Plate
- Shop class
- 5 to 25 HP rotary screw
- Duty cycle
- 100%, no cooldowns
- Dew point
- 38 F refrigerated
- Booth air
- OSHA Grade D + CO monitor
- Dealer
- Sullair since 1984
What size air compressor does my shop need for my lifts, tools, and paint booth?
When the DA sander bogs down mid-panel or the impact will not break a lug loose while the booth is spraying, the shop is out of CFM. Total the CFM of the tools that actually run at the same time, add the booth and blow-off load, then add about 30 percent headroom: most 2 to 4 bay shops land at 5 to 10 HP, and shops with a busy booth or blast cabinet at 15 to 25 HP. The sizing tool below does the math from your bay count and tools.
The shop air lineup
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Rotary Screw 5 to 25 HP
- Range
- 5 to 25 HP shop class
- Output
- 18 to 100 CFM
- Noise
- Enclosed, office-safe
- Use
- Multi-bay shop air
-
Refrigerated Dryers
- Dew point
- 38 F class
- Fixes
- Water in air lines
- Protects
- Paint finish, tools
- Style
- Cycling and non-cycling
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Breathing Air for Booths
- Standard
- OSHA Grade D
- Spec
- CGA G-7.1
- Monitoring
- CO monitor required
- Use
- Supplied-air respirators
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Shop Air Distribution
- Piping
- Loop layout, sized drops
- Storage
- Receiver at the booth
- Drains
- Auto drains, no puddles
- Install
- Factory-trained techs
45 + Years in Business
14 Midwest Locations
4.7 Star Google Rating
Shop air sizing tool
Pick your bay count and check the air users you actually run. The output is a CFM and HP range with the matching product path. Rule-of-thumb starting point; an engineer confirms it against your booth and piping.
Recommended shop system
Pick your bay count and air users above for a sizing range.
Run the numbers yourself
- CFM calculator: total the air tools, sanders, and booth load a shop runs at once before picking a compressor.
- Air receiver tank calculator: size the receiver at the booth so spray guns and blast cabinets do not drag pressure down.
- Compressed air leak calculator: put a dollar figure on the leaks bleeding pressure off your shop header.
What compressed air really costs
- 10% of US industrial electricity goes to compressed air Source: US DOE Compressed Air Sourcebook
- 20 to 30% of compressed air is typically lost to leaks Source: US DOE Compressed Air Sourcebook
- 75% of ten year compressor cost is energy, not purchase price Source: CAGI life cycle cost data
- under 2 hr average emergency response across our territory Source: Brabazon dispatch
Where shops burn compressed air
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Air tools and impact wrenches
Half-inch impacts pull 4 to 5 CFM in real use; the ratchet next to it adds more.
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Tire service
Bead seating, inflation, and tire changers that spike demand hard.
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Paint booth supply
Clean dry spray air plus Grade D breathing air for the painter.
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Blow-off and drying
Panel dry-off and part cleaning between prep and paint.
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Frame and body
Air-over-hydraulic frame equipment and body pulling posts.
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Lifts and pneumatics
Air-locking lifts and in-ground lift controls across the bays.
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Media blasting
The hungriest tool in the shop: a blast cabinet can outdraw everything else.
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HVAC service
Purge, pressure testing, and shop air for the service side.
The rules and fixes that matter in a shop
Four things separate a shop with reliable, paint-safe air from one fighting moisture, noise, and an OSHA citation. None of this is gated behind a form.
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OSHA Grade D breathing air
If a painter wears a supplied-air respirator in your booth, OSHA 1910.134 requires Grade D breathing air per CGA G-7.1, with carbon monoxide monitoring on oil-lubricated compressors. Shop air straight off the compressor does not qualify. The full requirement is on our breathing air page.
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Moisture control for paint
Fisheyes and blushing in a finish usually trace back to water or oil in the air line. A refrigerated dryer holding a 38 F class dew point, a filter train at the booth, and auto drains on the receiver are the standard fix, and cheaper than one repaint on a customer car.
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30 psi blow-off rule
OSHA 1910.242(b) limits cleaning blow-off to 30 psi when dead-ended. Relief-style safety nozzles on shop blow guns keep full flow for drying panels while staying compliant during an inspection.
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Noise in customer areas
An enclosed rotary screw runs in the high 60s dBA range, quiet enough to sit near the service write-up area. An 80-gallon piston unit in the same spot will be heard at the counter, which is why placement and enclosure choice matter in a retail shop.
Featured equipment for automotive shops
For a 3 to 6 bay shop with a booth, the setup we install most is a Sullair enclosed rotary screw in the 10 to 15 HP class with an integrated or matched refrigerated dryer, a receiver at the booth, and a filter train at the spray wall. It runs quietly enough for a customer-facing shop, holds a 38 F class dew point so finishes stay clean, and never needs a cooldown break on a busy Saturday. Models and pairings are on the rotary screw page, and booth respirator supply comes from the Grade D breathing air page.
When a rotary screw is the wrong buy: a small independent shop running
air in short bursts, an impact here, a tire there, does better with a good two-stage
piston compressor and a properly sized tank than with an oversized rotary screw that
short-cycles at low load. If your air use is intermittent, say so and we will quote the
right class of machine instead of the biggest one.
Typical project: multi-bay shop with a paint booth
Ending the Monday morning moisture fight in a busy body shop
A common scenario in Midwest body shops starts with paint defects and tools losing torque at the busiest bays. A walk-through often finds an aging piston compressor at 100 percent duty, no dryer, and water pooling in the booth regulator every Monday after weekend humidity soaks the tank. A typical Brabazon project replaces it with a shop-class Sullair rotary screw and a cycling dryer, re-pipes the drops to come off the top of the header, and adds a Grade D breathing air panel with CO monitoring at the booth. Once that is in place the moisture-related repaints stop, and shops usually put the equipment on a Brabazon preventive maintenance schedule to keep it that way.
Shop air support across the upper Midwest
Factory-trained technicians dispatch from 14 branches with an under 2 hour average emergency response. Find your nearest branch:
Questions engineers actually ask us
What size air compressor do I need for a 2 bay or 4 bay shop?
A 2 bay mechanical shop typically runs well on 5 to 7.5 HP delivering 18 to 28 CFM, and a 4 bay shop on 7.5 to 10 HP. Add a paint booth or blast cabinet and the number jumps: booths commonly add 15 to 30 CFM while spraying. Total the tools you actually run at once, then add about 30 percent headroom.
Why is there water in my air lines and how do I stop it?
Compressing air concentrates its humidity, and a working shop compressor can condense gallons of water on a humid day. The fix is a refrigerated dryer after the compressor, auto drains on the tank, and drops that come off the top of the pipe run. A dryer protects tools and paint at a fraction of what moisture defects cost.
Can I use shop air for my paint booth respirator?
No, not without making it Grade D breathing air first. OSHA 1910.134 requires CGA G-7.1 Grade D quality with CO monitoring for supplied-air respirators, which means a breathing air filtration panel or a dedicated breathing air source, not a tee off the shop header.
Is a rotary screw compressor worth it over a piston for my shop?
Yes once your shop pulls air steadily through the day: multi-bay shops with a booth are the classic case, because a rotary screw delivers 100 percent duty cycle, quieter operation, and dry consistent air. A small shop using air in short bursts is often better served by a two-stage piston, which we will tell you straight.
What CFM do common shop air tools use?
In real intermittent use: a half-inch impact wrench runs about 4 to 5 CFM, an air ratchet 3 to 4, a DA sander 8 to 12 continuous, a spray gun 9 to 14, and a blast cabinet 15 to 35 depending on the nozzle. Sanders, guns, and blasting are continuous loads, which is why they dominate sizing.
Who services automotive shop compressors near me?
Brabazon dispatches factory-trained technicians from 14 locations across Wisconsin, Illinois, Minnesota, and Missouri with an under 2 hour average emergency response. We have sold and serviced compressed air since 1978 and stock Sullair OEM parts.
Where to go next
Get a number sized to your bays, not a catalog page
Tell us your bay count, your booth, and your worst air complaint. An engineer will size the compressor, dryer, and piping as one system and quote it straight.