How do you ensure compatibility between metric hose fittings and hoses of different materials?

Ensuring compatibility between metric hose fittings and hoses of different materials is essential for maintaining a leak-free, durable, and efficient system. Several factors need to be considered to ensure proper fit and performance. 
Hose Inner Diameter (ID) and Outer Diameter (OD): The hose and fitting sizes must match. Metric hose fittings are typically sized based on the hose’s inner diameter, but it’s also important to check the outer diameter of the hose to ensure proper attachment and sealing.Fitting Thread Type and Size: Metric fittings come in various thread types, such as metric BSP (British Standard Pipe) or metric ISO threads. It’s crucial to ensure that the threads on both the hose and the fitting match exactly (e.g., M16x1.5 for a metric fitting). Using the wrong thread can lead to leaks or unsafe connections.
Hose Material vs. Fitting Material: Different materials used for hoses (rubber, PVC, stainless steel braided, Teflon, etc.) require compatible fittings to ensure they can withstand the pressures and environmental conditions. For instance:Rubber hoses generally work well with brass, steel, or stainless steel fittings.Teflon or PTFE hoses often require stainless steel fittings to handle higher chemical resistance and pressure ratings.
PVC hoses may require fittings that are made of PVC or compatible materials to avoid chemical reactions or damage.Chemical Resistance: Make sure the material of the hose and fitting are resistant to the same chemicals (e.g., oils, acids, alkalis) they will be exposed to. For example, stainless steel fittings are corrosion-resistant and may be compatible with a wider range of materials, but brass fittings might not be suitable for certain chemicals like acids.
Match the Pressure Rating: Ensure that both the hose and the fittings are rated for the same pressure. If either the hose or the fitting is rated for lower pressure than required, it could result in failures, leaks, or system malfunctions. Check the manufacturer specifications for the pressure ratings of both the hose and the fittings to ensure they match.
Burst Pressure: Also consider the burst pressure, which is the maximum pressure the hose and fitting can safely withstand before failure.
Operating Temperature Range: Ensure that the hose and fittings can operate within the same temperature range. For example, if the hose is designed to handle high temperatures, make sure the fitting material is also rated for such conditions. Similarly, if the hose is used in a cold environment, ensure the fittings won’t become brittle or crack.
Rubber hoses tend to degrade at higher temperatures, while stainless steel braided hoses may perform better in extreme temperature conditions.
Sealing Mechanism: Check the type of seal used for both the hose and the fitting. Common sealing methods include O-rings, gaskets, or compression fittings. Ensure that the sealing material in the hose and the fitting is compatible, especially in high-pressure or high-temperature applications, to avoid leaks.Rubber seals work well with many materials but may degrade with exposure to heat or chemicals.PTFE seals are often used in high-performance or chemical-resistant systems.
End Connection Type: The hose may have a barbed or swaged end, while the fitting may have a threaded, push-fit, or compression connection. The type of connection will dictate how the hose fits into the fitting, and ensuring compatibility is essential for a leak-free connection.Barbed fittings work well with hoses that have some flexibility, such as rubber hoses.Threaded fittings may require a clamp to secure the hose properly.
UV and Weather Resistance: If the hoses are exposed to outdoor conditions, such as sunlight or extreme weather, choose materials that can withstand UV exposure, such as rubber hoses with UV resistance or braided stainless steel hoses.Vibration Resistance: If the hose is part of an automotive or heavy machinery system where vibration is common, you may need to use fittings that can securely hold the hose in place to prevent loosening or damage.