Hydraulic Hose Pressure Ratings: Working, Burst and the 4:1 Safety Factor
Every hydraulic hose carries two pressure numbers, and confusing them is dangerous. Working pressure is what you design to; burst pressure is where it fails. The relationship between them, the safety factor, is why you should never run a hose near its burst number. This guide explains how to read a hose rating.
What is the difference between working pressure and burst pressure?
The short answer: working pressure, or maximum working pressure, is the highest pressure the hose is designed to operate at continuously and safely. Burst pressure is the pressure at which the hose actually fails in testing. For hydraulic hose the standard relationship is a 4:1 safety factor: burst pressure is at least four times the rated working pressure. You design to the working pressure, never the burst pressure.
The 4:1 safety factor
International standards, including SAE J517, require the burst pressure to be at least four times the published working pressure. So a hose rated 2,000 psi working must survive at least 8,000 psi before bursting. That margin is not spare capacity to use; it is there to absorb pressure spikes, temperature effects, impulse cycling and normal ageing of the hose. Running a hose above its working pressure eats into that margin and shortens its life or causes failure.
Why the margin matters: spikes and impulse
Rated working pressure assumes steady conditions. Real systems see pressure spikes from fast valves and shock loads, and repeated impulse cycles fatigue the reinforcement over time. The 4:1 factor is designed to cover exactly these effects, which is why you size to the working pressure and, on circuits with frequent spikes, choose a hose with extra margin or a higher impulse rating.
Reading a hose rating correctly
- Use the working pressure as your design ceiling, and keep the system maximum, including spikes, below it.
- Remember that working pressure falls as the hose bore increases, so check the rating for your specific dash size.
- The lowest-rated component in the assembly sets the limit: the hose, the fittings and the crimp must all meet the pressure, not just the hose.
Quick reference
| Term | What it means | How to use it |
|---|---|---|
| Working pressure | Max safe continuous pressure | Design ceiling |
| Burst pressure | Pressure at which it fails in test | Never a design target |
| Safety factor | Burst divided by working, 4:1 for hydraulics | Margin for spikes and ageing |
| Impulse rating | Cyclic pressure endurance | Check for high-cycling circuits |
Related range: Browse Velqor hydraulic hose pipes →
The goal is a hose that stays within its limits, whether you buy from us or not
We wrote this so you can read a hose rating properly and design to the working pressure with the 4:1 margin intact, wherever you source it. Never treat the burst number as usable headroom; it is your safety margin, not your operating range.
If you do want it sourced to spec, here is how we work: Velqor supplies hose and pressure-tested assemblies rated to your working pressure with the correct margin, and we confirm that the hose, fittings and crimp are all rated for the system, not just the hose. Tell us your working pressure and whether the circuit sees spikes, and we will specify with the right margin rather than the bare minimum.
Frequently Asked Questions
What is the safety factor for hydraulic hose?
The standard hydraulic safety factor is 4:1, meaning the burst pressure must be at least four times the rated working pressure. SAE J517 requires this margin, verified by hydrostatic burst testing.
Can I run a hose up to its burst pressure?
No. Burst pressure is a test-failure figure, not an operating limit. The gap between working and burst pressure is your safety margin for spikes, heat and ageing. Design to the working pressure only.
Why does working pressure drop as the hose gets bigger?
A larger bore puts more force on the reinforcement at the same pressure, so the rated working pressure decreases as dash size increases. Always check the pressure rating for your specific size.
Does the fitting or crimp affect the pressure rating?
Yes. The assembly is only as strong as its weakest part. The hose, the end fittings and the crimp must all be rated for the system pressure; a correctly crimped, matched assembly is what holds the rating.
How do I allow for pressure spikes?
Account for surge and impulse when choosing the working pressure, build in margin, and on circuits that cycle fast or shock-load frequently, choose a hose with a higher impulse rating.