In industrial applications, hose assemblies are critical components for fluid and gas transfer. However, a common confusion arises when a hose rated for 20 bar fails to perform beyond 8.4 bar in real-world conditions. While factors like fittings and crimping methods play a role, **temperature** is often the overlooked culprit. Today, we dive into how temperature fluctuations directly affect hose working pressure and what you can do to ensure optimal performance.
The Hidden Relationship Between Temperature and Pressure
Most hoses specify a “maximum working pressure” and “maximum operating temperature” in their documentation. This creates a misconception that both values can be achieved simultaneously. In reality, temperature dramatically alters a hose’s structural integrity
As temperatures rise:
1. Hose material softens, reducing its resistance to internal pressure.
2. Fitting grip weakens, compromising the connection between the hose and fittings.
3. Pressure ratings decrease, even if the temperature remains within the stated “maximum” range.
For example, a hose tested at 20°C (room temperature) for its 20-bar rating may lose over 50% of its capacity at elevated temperatures. This explains why some assemblies rated for 20 bar struggle to handle even 8.4 bar in high-heat environments.
How Temperature Affects Different Hose Types
Not all hoses respond to temperature equally. Below are key categories and their susceptibility to heat-induced pressure derating:
| Hose Type | Typical Applications | Temperature Sensitivity |
| Steam Hose | Hot water, steam | High sensitivity (similar to asphalt hoses) |
| Asphalt Hose | Hot oil, tar, petroleum-based products | Severe pressure loss at high temperatures |
| PVC Hose | Water, air (low-temperature environments) | Moderate derating above 40°C |
| Chemical Hose | Aggressive fluids (PTFE, XLPE liners) | Varies by liner material; PTFE resists heat |
| Air/Water Hose | General-purpose use | Limited tolerance for temperature swings |
| Soft-Wall Hose | Food-grade or natural rubber applications | High flexibility but low heat resistance |
| PTFE Hose | High-purity or corrosive fluids (braided) | Excellent heat resistance but check specs |
Calculating Actual Working Pressure
To determine the safe working pressure of a hose at elevated temperatures:
1. Identify the temperature derating factor** for your hose type (provided by manufacturers).
2. Multiply the derating factor by the hose’s rated pressure(tested at 20°C).
Example:
A steam hose rated for 20 bar at 20°C might have a derating factor of 0.42 at 100°C.
Actual working pressure = 20 bar × 0.42 = 8.4 bar.
Key Takeaways for Safe Hose Operation
1. Never assume maximum pressure and temperature are simultaneous.
2. Consult derating charts** specific to your hose type and application.
3. Monitor operating temperatures rigorously—even brief spikes can compromise safety.
4. Prioritize hoses designed for high-temperature applications(e.g., PTFE or steam hoses) when heat is unavoidable.
Conclusion
Temperature’s impact on hose pressure is non-negotiable in industrial safety. By understanding derating principles and selecting hoses tailored to your thermal environment, you can prevent failures and extend equipment lifespan. Always verify specifications with your supplier and apply temperature-adjusted pressure limits to ensure reliable performance.
For tailored solutions or derating data for your hose systems, contact us today
Post time: May-26-2025