Pipeline systems
Gas-specific probe
A gas-specific probe is the plug-in connector on a hose or medical device that fits only the terminal units of one medical gas or vacuum service, so that equipment cannot be connected to the wrong gas.
ISO 9170-1 requires terminal units to be gas-specific and to prevent interchange between gases and services, but it does not specify the dimensions of probes. Those come from national standards: the British BS 5682 sets the dimensions of probes and terminal units, the German DIN 13260-2 the dimensions and allocation of probes and gas-specific connection points, and the French NF S90-116 the sockets and related probes. The World Health Organization notes that each connector style uses key-like indexing so that the fittings of each gas service connect only with their own type.
Each gas has its own probe, and gas-specific connections are also identified by symbol and colour. The 2025 edition of DIN 13260-2 adds a gas-specific probe for oxygen 93.
HTM 02-01 (2026), the NHS England guidance, checks probe fit at commissioning and in service. Form B24 verifies that each terminal unit is gas-specific and securely retains the appropriate probe, and all terminal units should be tested quarterly by inserting a blank probe to check gas-specificity, mechanical function and leaks.
Sources
- ISO 9170-1:2017, Terminal units for medical gas pipeline systems (ISO summary)
- HTM 02-01 (2026) Part A, form B24 and references (BS 5682:2015) (NHS England)
- HTM 02-01 (2026) Part B: Operational management, terminal unit maintenance (NHS England)
- DIN Media, DIN 13260-2:2025-06
- AFNOR, NF S90-116 (October 2020), store page
- WHO, Foundations of medical oxygen systems (2023), outlet connector styles
Ultra Controlo figures come from its technical datasheets. Third-party facts were read at the source on the date shown.