What does a workshop use compressed air for?
Workshops cover a wide range: fabrication and welding shops, machine shops, maintenance workshops inside factories, tool rooms, joinery, motor rewinding, pump and valve repair, and plant maintenance bays. Typical air users are:
- Grinders, sanders, drills, impact wrenches and nut runners.
- Chipping hammers and needle scalers for weld cleaning.
- Blow guns for cleaning parts and machines.
- Spray guns for painting and coating.
- Small sandblasting cabinets.
- Pneumatic presses, clamps and fixtures on machine tools.
- Air motors, hoists and pumps for oil and grease.
For automotive service bays, tyre changers, wheel balancers, lifts and body shops, see our dedicated page on garage compressed air. This page covers the shared method for general and industrial workshops.
Step 1: build a user schedule
Start by writing down every air user. For each one record the information below. Tool manufacturers publish air consumption, normally in cfm or litres per minute at a stated pressure.
| Field | What to record | Why it matters |
|---|---|---|
| Equipment | Tool or process name and size | Different sizes of the same tool use very different air |
| Air consumption | Flow at working pressure from the tool data | Basis of the demand estimate |
| Pressure at tool | Required inlet pressure | Sets the system pressure with losses |
| Use pattern | Seconds or minutes per use, uses per hour | Separates bursts from sustained load |
| Simultaneity | Which tools run at the same time | Determines the peak |
| Air quality | Dry, filtered, oil-free for paint or instruments | Sets treatment needs |
| Location | Bay or outlet position | Drives the pipe layout and hose lengths |
Do not guess a “diversity factor”. Watch the work for a few shifts, or log pressure and compressor running, to see which combinations really happen. A fabrication shop where three grinders and a chipping hammer run together after every weld is very different from a maintenance shop where tools are used for seconds at a time.
Step 2: work out real demand
Separate two kinds of load:
Across brands
Models we supply and service
Manufacturer product images, shown to identify machines we sell, service and support. Brand names are trademarks of their owners.
- Sustained users – grinders, sanders, spray guns and blast cabinets that run for minutes at a time. These set the average demand that the compressor must deliver continuously.
- Short bursts – impact wrenches, blow guns and clamps. These can often be met from receiver storage.
Add the sustained users that run together, allow for the bursts, then add a margin for leaks and future tools. Measured leakage in older workshops is often a meaningful share of total air, so fix leaks before buying a bigger compressor. Our compressed air demand calculator helps organise the numbers.
As a worked example, consider a fabrication bay with two 180 mm angle grinders at about 35–40 cfm each, one needle scaler at about 10 cfm and a blow gun at about 8 cfm used occasionally. If both grinders and the scaler run together for long periods, sustained demand is about 80–90 cfm. Adding the blow gun as a burst and a leakage and growth margin, a compressor delivering around 100–110 cfm of FAD at working pressure, with a sensible receiver, is a reasonable starting point. Replace the example figures with your own tool data.
Step 3: set pressure from the tool back to the compressor
Pressure is lost at every step between the compressor and the tool: dryer, filters, pipework, valves, quick couplings, filter-regulator-lubricator and hose. Small hoses and cheap couplings cause surprising losses. Work backwards:
- Required pressure at the tool inlet, typically about 6–6.5 bar (87–94.3 psig).
- Add losses in the hose, coupling and regulator at the tool’s flow.
- Add losses in pipework and treatment equipment.
- Add the pressure band of the compressor control (cut-in to cut-out, or load to unload).
The result is the compressor’s working pressure. Do not simply raise the pressure to cover a poor network: about 7% more power is needed for each extra bar, and higher pressure increases leakage. Our pressure budget builder is useful here.
Step 4: choose the compressor type
| Workshop pattern | Usually suits | Reason |
|---|---|---|
| Small shop, intermittent tools, a few hours a day | Tank-mounted piston compressor, single or two-stage | Low cost, simple, storage handles bursts |
| Medium shop, regular tools, one shift | Two-stage piston compressor or small rotary screw | Piston for moderate duty; screw if loaded most of the shift |
| Busy shop, sustained grinders and painting, long hours | Rotary screw compressor with receiver and dryer | Designed for continuous duty, steadier pressure |
| Maintenance shop inside a plant | Connection to plant air, with local receiver if needed | Avoids a separate machine; check pressure and quality |
| Temporary or outdoor work | Portable diesel or rental electric compressor | No permanent installation needed |
Compare machines on free air delivery (FAD) at working pressure, not on motor kW or piston displacement. For piston compressors, check the manufacturer’s limit on loaded running time and starts per hour. Our rotary screw vs reciprocating comparison explains the choice in more detail.
Step 5: storage and air treatment
A receiver smooths bursts, reduces compressor starts and lets condensate settle. Size it from the peak flow, its duration and the pressure band you can accept; a separate receiver near a heavy intermittent user can help. See air receiver tank sizing.
Workshop air carries water and, from lubricated compressors, oil. In humid monsoon weather a compressor can produce litres of condensate a day. Treatment typically means:
- An aftercooler and separator, often built into screw packages.
- A refrigerated dryer giving a pressure dew point of about +3 °C for general tools and painting.
- General-purpose and coalescing filters, with activated carbon for spray painting where needed.
- Automatic drains on the receiver, dryer and filters, with condensate handled properly rather than poured into drains.
- Point-of-use filter-regulator-lubricators matched to each tool.
Step 6: pipework and outlets
Good pipework is the cheapest efficiency measure in a workshop:
- Size the main pipe for full flow with low pressure drop. Use our pipe sizing calculator.
- A ring main gives better pressure at the far end than a single long run.
- Slope pipes slightly in the flow direction with drain legs at low points.
- Take drops off the top of the main so water does not run into the tools.
- Fit an isolation valve at each drop, and use quick couplings and hoses sized for the tool’s flow.
- Keep hose runs short; a long, small hose can lose more pressure than the entire pipe system.
Common workshop air problems
| Problem | Typical cause | Fix |
|---|---|---|
| Tools weak at far bays | Undersized pipe, long thin hoses, restrictive couplings | Ring main, larger drops, better couplings |
| Compressor never stops | Demand above FAD, leaks, worn compressor | Leak survey, FAD check, resize if needed |
| Water in tools and paint | No dryer, drains not working, drops off the bottom of the main | Dryer, auto drains, correct drop take-offs |
| Compressor overheats in summer | Poor ventilation, dirty cooler or fins | Ventilation, cleaning, relocation |
| High electricity use | Pressure set high, leaks running overnight | Lower pressure, isolate at night, fix leaks |
How Reddy Compressors helps
We are an independent multi-brand compressed-air specialist based at Tarnaka, Secunderabad, serving workshops and industry since 2002. We:
- Build the user schedule with you and recommend compressor size, receiver, treatment and pipework.
- Sell new and used/refurbished piston and screw compressors, dryers, filters and receivers from ELGi, Atlas Copco, Ingersoll Rand, KAESER, Chicago Pneumatic and other brands. We are not an authorised dealer of any brand. We have tie-ups with all major and reputed brands.
- Service, repair and maintain workshop compressors through more than 20 service engineers and technicians, with AMC options.
- Carry out leak checks and air audits on existing systems.
- Supply spare parts identified from the machine’s nameplate, model and serial number, with fit confirmed before quoting.
- Rent compressors while a workshop machine is repaired or during a busy contract.
Our service teams cover the whole of Telangana and Andhra Pradesh, and we supply across India. Call +91 99590 60718 or +91 92468 88812.
What to send us
- List of air tools and processes, with model or size
- How many tools run together and for how long
- Working hours per day and days per week
- Existing compressor nameplate photos, if any
- A rough layout of bays and outlets
- Any problems: low pressure, water, high bills or overheating
Frequently asked questions
What size air compressor do I need for my workshop?
List each tool’s air consumption at working pressure, identify which tools run together for sustained periods, and add a margin for short bursts, leaks and growth. The compressor’s free air delivery at working pressure must exceed that sustained demand. Floor area, staff numbers and motor power are not reliable sizing methods. A receiver handles short peaks.
What pressure should a workshop compressor run at?
Most air tools need about 6–6.5 bar (87–94.3 psig) at the inlet. Add losses through hoses, couplings, regulators, filters, dryer and pipework, plus the compressor’s control band. Many workshops end up at 7–10 bar (101.5–145 psig). Avoid running higher than needed, because each extra bar costs about 7% more power and increases leakage.
Should a workshop use a piston or screw compressor?
Piston compressors suit intermittent use and smaller shops, with low purchase cost and simple maintenance. Rotary screw compressors suit workshops where tools run for long periods across a shift, because they are designed for continuous loaded running and give steadier pressure. The deciding factor is the duty pattern, not the word workshop.
Why are my air tools weak at the far end of the workshop?
Usually because of pressure drop in undersized pipework, long thin hoses or restrictive quick couplings, rather than a weak compressor. Measure pressure at the tool while it runs. A ring main, larger drops, shorter hoses and full-bore couplings often fix the problem without changing the compressor or raising its pressure setting.
Do I need an air dryer in a workshop?
If you paint, run precise pneumatic equipment or suffer water at tools, yes. Compressed air in Indian monsoon conditions carries a lot of water that condenses in pipes and tools. A refrigerated dryer giving about +3 °C pressure dew point, with filters and automatic drains, protects tools and finishes and is the usual choice for workshops.
How can I reduce compressed-air costs in my workshop?
Fix leaks, lower the pressure setting to what tools actually need, switch off or isolate the system when the shop is closed, and stop using blow guns for general cleaning. Check that pipework is not forcing a higher pressure. Our engineers can carry out a leak check and simple audit to show where air is going.
Related pages
Calculators and worked examples
These tools give indicative figures for screening, comparison and for preparing an enquiry. They run in your browser and send nothing. No prices or tariffs are assumed: enter your own to see costs. Efficiencies and other figures shown are example values: replace them with your own. Results are not a performance guarantee or a design certificate; final selection is confirmed by a service engineer against the machine data sheet and the site.
Compressed air demand estimate
Add up the air your tools and processes use, apply duty and simultaneity, then add leakage and growth allowances to reach a capacity to enquire about.
The worked example below shows the method with fixed numbers. Turn on JavaScript to change the inputs.
Worked example
Inputs
- Unit for the air each tool uses: L/s
- Group A: number of tools: 6
- Group A: free air each (in the unit above): 4
- Group A: duty (%): 40
- Group B: number of tools: 2
- Group B: free air each (in the unit above): 15
- Group B: duty (%): 60
- Group C: number of tools: 1
- Group C: free air each (in the unit above): 40
- Group C: duty (%): 80
- Simultaneity of all tools (%): 65
- Leakage allowance (%): 15
- Growth allowance (%): 10
Result
- Connected demand: 94 L/s = 199 cfm
- Average demand (duty-weighted): 59.6 L/s = 126 cfm
- Simultaneous peak: 61.1 L/s = 129 cfm
- Design basis (higher of average and peak): 61.1 L/s = 129 cfm
- Design capacity with allowances: 77.29 L/s = 4.64 m³/min = 163.8 cfm
Method. Average demand = Σ(number × air per tool × duty). Peak = Σ(number × air per tool) × simultaneity. The peak can never be lower than the average, so the design basis is the higher of the two. Design capacity = design basis × (1 + leakage) × (1 + growth).
What to take from it. Leakage and growth allowances move the answer as much as any single tool. Where you can, replace catalogue figures with measured ones.
Technical content reviewed by D. Srinivas Reddy, Managing Partner and service engineer, Reddy Compressors. Last updated 17 October 2026. How our engineering content is reviewed.
Pressure budget and the cost of excess pressure
Add up the pressure that is lost between the compressor and the point of use, and see what a lower set-point would be worth.
The worked example below shows the method with fixed numbers. Turn on JavaScript to change the inputs.
Worked example
Inputs
- Pressure needed at the point of use (bar g): 6
- Dryer and filter loss (bar): 0.5
- Piping loss (bar): 0.3
- Hose, fittings and regulator loss (bar): 0.3
- Control band and safety margin (bar): 0.3
- Current compressor set-point (bar g): 8
- Compressor input power (kW): 75
- Saving per bar reduced (%): 7
- Running hours per year: 6000
Result
- Total pressure losses: 1.1 bar
- Control band and safety margin: 0.3 bar
- Compressor pressure needed: 7.4 bar g (point of use + losses + band and margin)
- Possible reduction from current set-point: 0.6 bar
- Indicative energy saving: 18,900 kWh per year
- Indicative cost saving: Enter your electricity tariff (cost per kWh) above
Method. Required compressor pressure = point-of-use pressure + sum of losses. Savings = power × (reduction in bar) × saving per bar. A saving of roughly 6–8% of compressor power per bar of pressure is commonly quoted; it is indicative and varies with machine type and control, so edit it to suit.
What to take from it. The saving is real only if the farthest and most demanding point still works at the lower set-point. Prove it before you change the setting.