Temporary air fuel logistics calculator

Why fuel logistics stops more jobs than compressor capacity

A diesel compressor can be correctly sized for flow and pressure and still stop on site. The onboard tank may be too small for a double shift, the night refuelling round may be missed, a tanker may not reach a hilltop drilling location in the monsoon, or the plan may assume the whole nominal tank volume is usable. Each of these is a logistics failure, not an engineering one, and each is preventable on paper before mobilisation.

The calculator on this page is a planning tool. It is not a combustion or engine-performance model. It turns runtime, load-state fuel rates and project duration into fuel volume, tank autonomy, refuelling interval, delivery quantity and reserve stock.

What the calculator works out

Mode	Main output	Typical use
Shift fuel plan	Litres per shift and per day	Daily fuel issue to operators
Tank autonomy	Hours of running from usable tank volume	Checking a machine can complete a shift unattended
Refuelling plan	Refill interval and number of refuels per day	Planning the refuelling round
Delivery plan	Litres per delivery and trips per week	Ordering from the fuel supplier
Fleet mode	Combined demand of several compressors and generators	Multi-machine sites and work fronts
Scenario mode	Low, base and high burn and runtime cases	Testing the plan against uncertainty

Inputs and where they should come from

Fuel rate for each operating state in litres per hour: loaded, part-loaded, unloaded/idling and stopped. Use measured site data, a verified supplier curve at a defined load or recorded fuel issue on similar jobs. Typical litres per hour depend heavily on load, pressure and ambient conditions, so a single brochure figure is only a starting point.
Hours in each state per shift, from the work plan or from the controller’s hour meters.
Nominal tank volume, plus the practical fill level and the level you never run below.
Reserve policy, stated as the hours or delivery delay the site must survive.
Fuel on hand and the site storage capacity.
Deliverable volume per trip of the bowser or tanker.

The method and formulas

Fuel per period is the sum of each state’s fuel rate multiplied by the time spent in that state:

Fuel per period = Σ (fuel rate in state i × hours in state i)

Usable tank volume is less than nominal volume, because tanks are rarely filled to the brim and should never be run dry:

Usable volume = nominal volume × (fill fraction − retained fraction)

Average burn is period fuel divided by running hours, and theoretical autonomy is usable volume divided by average burn. The planned refuelling interval should be shorter than theoretical autonomy, because refuelling at the last minute leaves no margin for a missed round.

Reserve stock covers the longest credible gap in supply:

Delay reserve = average site burn × maximum planned delivery delay

Delivery quantity is future consumption to the next delivery plus reserve, minus fuel already on hand. Trips are delivery quantity divided by the deliverable volume per trip, rounded up.

Worked example: two compressors on a drilling job

The figures below are invented for arithmetic only and do not represent any particular machine. Two diesel portables run a 20-hour working day. Each spends 14 hours loaded, 4 hours unloaded and 2 hours stopped.

State	Hours	Assumed rate (L/h)	Fuel (L)
Loaded	14	40	560
Unloaded	4	12	48
Stopped	2	0	0
Per machine per day	20	—	608

The two machines need 1,216 litres a day. Full-load burn multiplied by 20 clock hours would give 1,600 litres, overstating demand by about a third and making the plan look more expensive and difficult than it is.

Suppose each tank holds 500 litres nominal, is filled to 95% and should never go below 10%. Usable volume is 500 × 0.85 = 425 litres. Average burn while running is 608 ÷ 18 ≈ 33.8 L/h, so theoretical autonomy is about 12.6 hours. Each machine therefore needs at least two refuels a day, and a sensible plan is to refuel at each shift change rather than waiting.

If the fuel supplier can be two days late in the monsoon, delay reserve is 1,216 × 2 = 2,432 litres. With weekly deliveries, the order is about 7 × 1,216 + 2,432 minus fuel on hand. Check that site storage can hold that volume safely; if it cannot, deliver more often instead.

How to interpret the results

If autonomy is shorter than a shift, plan a mid-shift refuel or ask for a machine with a larger tank or an auxiliary tank.
If the reserve exceeds safe storage, increase delivery frequency rather than overfilling.
If the low and high scenarios differ widely, measure actual fuel issue during the first week and update the plan.
Compare litres per day with recorded fuel issue. A sudden rise at the same air demand can point to blocked air filters, a worn airend, leaking hoses or a control fault, not just heavier work.

Limits of the calculation

The calculator does not predict engine fuel consumption from first principles, and it is only as good as the fuel rates entered. It does not account for fuel theft or spillage unless you add an allowance, and it does not replace site rules for fuel storage, bunding, fire safety and handling. For electric temporary compressors, use the electrical tools instead of converting power to a diesel equivalent. High summer ambient in Telangana and Andhra Pradesh, dust and continuous high-pressure drilling can all change fuel use, so review the plan once real data is available.

Planning checklist before mobilisation

Confirm fuel rates by state for each machine, with the source noted.
Agree who refuels, at what times and with what equipment.
Check tanker access to every work front in all weather.
Set a minimum stock level and who is called when it is reached.
Arrange fuel filtration and water separation at the storage tank; contaminated diesel is a common cause of site stoppages.
Align refuelling with the service plan; on our hire jobs, oil change and servicing are done every 300 running hours.

Fleet and multi-work-front planning

On larger jobs the compressors are rarely the only diesel users. Generators, lighting towers, welding sets and pumps often draw from the same storage. Enter every consumer in the fleet table so the site total reflects real demand, then split it by work front if machines are far apart. A drilling site with rigs spread over several kilometres may need a bowser round rather than one central tank, and the round must reach every machine before its usable volume runs out.

Record actual fuel issued against each machine every day. After the first week, replace the assumed fuel rates with measured averages for each machine and rerun the plan. This turns a preliminary estimate into a reliable schedule and highlights any machine whose fuel use is drifting upwards, which is often the first sign that it needs attention.

How Reddy Compressors helps

Reddy Compressors, based at Tarnaka in Secunderabad, has supplied temporary compressed air since 2002 from our own rental fleet of 50–2,000 cfm at 2–30 bar, diesel and electric, with operators where needed. We sell, rent and service ELGi, Atlas Copco, Ingersoll Rand, KAESER, Chicago Pneumatic and other makes as an independent multi-brand specialist, not an authorised dealer. We have tie-ups with all major and reputed brands.

For a hire, we help you brief duty, runtime and fuel arrangements together. On round-the-clock hire at a steel plant in Andhra Pradesh, for example, our 450 cfm diesel portable ran 24 hours a day with operators on 12-hour shifts and an oil change and service every 300 running hours, so fuel and service rounds had to fit the shift pattern. Generators for the same site can be arranged through Reddy Generators, which is under the same management. Our service teams cover the whole of Telangana and Andhra Pradesh, and we supply equipment across India.

What to send us

Site location, access route and any restrictions on fuel deliveries.
Air demand: flow, pressure and the tools or process it serves.
Working hours per day, number of shifts and project duration.
Who will supply fuel and the size of any site storage tank.
Whether you need operators, generators or electric machines instead of diesel.

Frequently asked questions

How much diesel does a portable air compressor use per hour?

It depends mainly on how hard the machine is working. A compressor running fully loaded at its rated pressure burns far more than one running unloaded, and ambient temperature, altitude and engine condition also matter. Use the supplier’s fuel curve at your load, or recorded fuel issue on a similar job, for each operating state. Then let the calculator combine those rates with the hours in each state.

Can I use full-load fuel consumption for the whole project?

Only if the compressor genuinely runs fully loaded the whole time, which is rare. Most site machines spend part of each shift unloaded or stopped while drilling rods are changed, blasting pots are refilled or crews take breaks. Multiplying full-load burn by clock hours overstates fuel demand and cost. A state-based calculation, checked against measured fuel issue, gives a more realistic plan.

Why should I not count the full fuel tank capacity?

Tanks are rarely filled to the brim, and running them nearly empty risks drawing sediment and water into the fuel system or air-locking the engine. The usable volume is the difference between the practical fill level and the minimum level you keep. Planning refuelling from usable volume, not nominal capacity, avoids a machine stopping before the next refuelling round.

How much reserve fuel should a site keep?

Set the reserve as the length of delay the site must survive, such as a missed delivery, a monsoon road closure or a weekend without supply, then multiply it by the average daily burn. Check that the reserve fits safely within permitted storage. If it does not, arrange more frequent deliveries rather than holding more fuel than the site can store safely.

How do I work out the number of fuel tanker trips?

Add the fuel needed until the next delivery to the reserve, subtract the fuel already on site, and divide by the volume the tanker can actually deliver on one trip. Round up to whole trips. Repeat the calculation for each work front if they are far apart, because one central tank may not be practical when the compressors are spread across a large site.

Is an electric compressor better than diesel for a long temporary job?

Where a reliable power supply of sufficient capacity is available near the work, an electric compressor removes fuel logistics and usually costs less to run. Where power is weak, distant or absent, diesel remains practical. Compare the two on energy, cabling, generator needs and duration. Our rental fleet includes both, and we can help you weigh them for your site.

Plan your temporary air package WhatsApp us