# BS (HTM) outlet

A BS outlet is a medical gas terminal unit built to the British standard BS 5682, which sets the dimensions of probes and terminal units; HTM 02-01 (2026), the NHS England pipeline guidance, asks for every terminal unit to conform to BS 5682 and BS EN ISO 9170-1.

HTM 02-01 (2026) Part A references BS 5682:2015, Dimensions of probes and terminal units for medical gas supply systems. BS EN ISO 9170-1 makes [terminal units](https://library.ultracontrolo.com/glossary/terminal-unit/) gas-specific but does not specify the dimensions of probes, so the British probe and socket geometry comes from BS 5682. Gas-specific connections are also identified by symbol and colour, and HTM 02-01 Part B notes that BS 5682 and BS EN ISO 9170-1 terminal units have an automatic isolating valve, or check plate, in the first-fix assembly.

The World Health Organization lists the British BS 5682 style among the national connector styles, with the French NF S90-116 and German DIN 13260-2 styles, and each style uses key-like indexing so that the fittings of each gas service connect only with their own type. In service, HTM 02-01 asks for all terminal units to be tested quarterly by inserting a blank [probe](https://library.ultracontrolo.com/glossary/gas-specific-probe/) to check gas-specificity, mechanical function and leaks.

## Sources

- [HTM 02-01 (2026) Part A, paragraph 3.9 and references (NHS England)](https://www.england.nhs.uk/wp-content/uploads/2016/05/health-technical-memorandum-02-01-medical-gas-pipeline-systems-part-a-design-installation-validation-verification-aug-2026.pdf)
- [HTM 02-01 (2026) Part B: Operational management, terminal unit maintenance (NHS England)](https://www.england.nhs.uk/wp-content/uploads/2016/05/health-technical-memorandum-02-01-medical-gas-pipeline-systems-part-b-operational-management-aug-26.pdf)
- [ISO 9170-1:2017, Terminal units for medical gas pipeline systems (ISO summary)](https://www.iso.org/standard/67451.html)
- [WHO, Foundations of medical oxygen systems (2023), outlet connector styles](https://iris.who.int/server/api/core/bitstreams/4ad6f5fd-089e-4142-8439-b64e98d816d8/content)

Reviewed: 2026-10-22. Ultra Controlo engineering. https://library.ultracontrolo.com/glossary/bs-outlet/