Unlike standard metal tubing, flexible hoses allow motion between two end points for easier routing over, under, through, or around obstacles. They’re often used to transport corrosive or flammable fluids and operate under high pressure, so it’s crucial to install them correctly.
Only competent qualified experts should attempt to install flexible hoses to ensure they meet the relevant standards for safe operation. It’s essential to choose the correct type of hose and hose fittings for the specific application and location, or you may be looking at disastrous consequences.
For example, a stainless steel hose would be suitable for gases or liquids under high temperatures and pressures, ideal for use in heating or ventilation and the automotive or power generation industries. Meanwhile, a composite hose would be the best choice for working with petrochemicals due to its higher resistance against corrosion.
Once you’ve identified which type of flexible hose is appropriate for your usage, read this guide on installing flexible hoses to ensure that they meet or exceed the required parameters and that your configuration doesn’t limit their lifespan.
Flexible hose installation checklist
Follow this straightforward run-through to make sure your flexible hose is fitted correctly.
- Check there is no visible damage to the flexible hose prior to installation.
- Make sure the hose is a sufficient length to create a smooth curve without stretching or twisting.
- Use the appropriate type and size of tools to secure the fittings.
- Allow some slack on the straight ends of the hose, as over-tightening can cause stress corrosion cracking.
- Do not bend hoses near the fittings. If there’s a tight bend required, use elbow fittings to join hoses instead.
- Ensure the ends are sealed securely, especially for insulated hoses where a build-up of moisture can cause them to fail.
- Check that the hose isn’t rubbing against any other surfaces in its installed position.
- Flush the circuit to clear any debris and pressure test to make sure all connections are secure.
Hose assemblies should undergo periodical inspections to identify any issues before serious failures potentially occur. Look out for the following:
- Frayed or bulging steel braiding
- Deformations such as twisting or flat spots
- Slippage, cracks, or dents
- Loose fitting attachments or covers
- Contact with adjacent piping or machinery
- Indications of corrosion
If you notice that any of these faults are present, repairs or replacements will be needed.
Tips for installing flexible hose
There are several common causes of flexible hose failure that should be avoided at all costs. By following these tips, you’ll make sure that your hose installation is secure, effective, and long-lasting.
Handle flexible hose with care
Lift and carry metal hoses carefully to prevent abrasions prior to installation – never drag them along the floor or let them make contact with other objects or materials in the vicinity.
When not in use, flexible hoses should be stored away from fumes and potential spillages, such as sprays and weld splatter.
Torque distorts the hose and creates more stress on the twisted area, reducing its strength and eventually resulting in premature failure.
Only bend the hose gently into a natural curve rather than twisting laterally. Avoid accidental torque by holding the hose in place while the fittings are tightened.
No out of plane flexing
You can avoid twisting the hose and damaging wire reinforcement by only bending the hose in one plane. If the hose is bent in multiple planes, it reduces the hose’s pressure capacity.
Alternatively, you can use multiple sections of hose coupled and clamped between bends if multi-plane bending is unavoidable in the installation space.
No axial extension or compression
Flexible hoses must be properly anchored and supported to absorb movement, as excessive weight will compress the hose and relax the tension.
This puts the assembly at accelerated risk of structural failure if the hose is not appropriately guided.
No sharp bends or over-bending
Do not exceed the recommended bend radius of the product, because bending in multiple places and too close to fittings creates excessive strain that can result in leakage from fatigue cracks.
To prevent over-bending and sharp bends, allow extra length for expansion and contraction when cutting the hose and use elbow fittings or swivel joints to connect smaller sections of hose.
Always provide adequate support and protection
When bent into a curve, both ends of the hose must be supported to prevent sagging. However, you should never over-tighten the fittings to keep the ends straight, as this restricts movement and can result in bulging.
You should use clamps on the fittings to hold the hose in place away from adjacent surfaces, and consider protective hose covers as an extra defence against abrasion.
Route hoses appropriately
Plan the hose routing in advance as much as possible to avoid stacking hoses or twisting them around each other.
Cluttered hose assembly isn’t only unpleasant to look at, but it also causes abrasion and makes safety maintenance much harder.
You should also prevent external exposure to excessive heat or corrosive or flammable chemicals that can damage the outer surface.