Can the Quick coupling plug with hose end, NITTO KOHKI HI CUPLA, brass be used with fluids other than water and still meet the 10 bar and specified flow rates?

Short answer: Not recommended without confirmation from the manufacturer. Reasoning: - The specification for the Quick coupling plug with hose end, NITTO KOHKI HI CUPLA, brass explicitly states it is "designed for water installations." That implies sealing materials, plating/finish and internal clearances are selected for water (and similar nonâaggressive, lowâviscosity fluids). - The body material (brass) can tolerate many fluids, but compatibility depends on the seal/elastomer and any internal coatings. Aggressive fluids (strong acids/alkalis, solvents, petroleum products, chlorinated hydrocarbons) can swell, harden or dissolve seals and degrade performance or cause leaks. - Pressure/flow ratings (10 bar working pressure; the listed flow rates at 5 bar) are valid only when the medium and operating conditions match the tested water conditions. Using a more viscous fluid or one that causes seal wear may reduce flow or lower safe pressure. - The note that "the medium must flow from the socket to the plug" is important for correct valve behavior; reversing flow or using entrained solids can damage the coupling. Recommendation: Contact Nitto Kohki with the exact fluid identity, temperature, operating pressure, and duty cycle to obtain approval or specified compatible seal materials. If manufacturer confirmation is not available, select a coupling explicitly rated for the intended fluid.

Is the Quick coupling plug with hose end, NITTO KOHKI HI CUPLA, brass suitable for potable water installations and compliant with drinking-water standards?

Quick coupling plug with hose end, NITTO KOHKI HI CUPLA, brass - based on the provided description: it is designed for water installations, made of brass, and has suitable working pressure and flow rates. However, the description does not state compliance with potable/drinking-water standards (e.g., NSF/ANSI 61, WRAS, KTW). Therefore you cannot assume it is certified for potable water without explicit manufacturer certification. Recommendation: request manufacturer documentation or certification declaring suitability for drinking-water use.

Does the Quick coupling plug with hose end, NITTO KOHKI HI CUPLA, brass require a specific flow direction from socket to plug?

Yes. The Quick coupling plug with hose end, NITTO KOHKI HI CUPLA, brass requires the medium to flow from the socket to the plug. The product is a plug without valve (hose end) designed for water installations; materials and performance: brass body, working pressure 10 bar, and flow rates at 5 bar of 4000 l/min (1"), 3200 l/min (3/4"), 2600 l/min (1/2"), 1600 l/min (3/8") and 1000 l/min (1/4"). Note specifies that the medium must flow from the socket to the plug.

Quick coupling plug with hose end, NITTO KOHKI HI CUPLA, brass

All products, General-purpose low-pressure quick couplings/

Additional information

Material	B – brass (bronze)

Nitto Kohki HI CUPLA series plug without valve with hose end, featuring excellent durability and vibration resistance. Designed for water installations. Material: brass. Working pressure: 10 bar. Flow rate: 4000 l/min (1″), 3200 l/min (3/4″), 2600 l/min (1/2″), 1600 l/min (3/8″), 1000 l/min (1/4″) at a pressure of 5 bar. Note: the medium must flow from the socket to the plug.

List of product variants

Article number	Product variant name	Nominal inner diameter	Working pressure [bar]
NK-20PH-B	HI CUPLA quick coupling plug, for 1/4" hose, brass	-	10
NK-30PH-B	HI CUPLA quick coupling plug, for 3/8" hose, brass	-	10
NK-400PH-B	HI CUPLA quick coupling plug, for 1/2" hose, brass	-	10
NK-40PH-B	HI CUPLA quick coupling plug, for 1/2" hose, brass	-	10
NK-600PH-B	HI CUPLA quick coupling plug, for 3/4" hose, brass	-	10
NK-800PH-B	HI CUPLA quick coupling plug, for 1" hose, brass	-	10

Nitto Kohki HI CUPLA series plug without valve with hose end, featuring excellent durability and vibration resistance. Designed for water installations. Material: brass. Working pressure: 10 bar. Flow rate: 4000 l/min (1″), 3200 l/min (3/4″), 2600 l/min (1/2″), 1600 l/min (3/8″), 1000 l/min (1/4″) at a pressure of 5 bar. Note: the medium must flow from the socket to the plug.