# Emergency supply inlet

An emergency supply inlet, or emergency inlet port, is a pipeline connection through which a mobile supply, such as a mobile liquid oxygen VIE, can feed a medical gas network in an emergency; HTM 02-01 (2026), the NHS England guidance, asks for such ports to be considered at design stage.

HTM 02-01 (2026) asks for emergency inlet ports to be considered during the informed design process. It notes that in some instances a fixed manifold system will remove the need for one, that mobile vacuum insulated evaporators (VIEs) were not readily available for immediate delivery and connection at the time of writing, and that adequate resilience in the design should remove the need for these ports.

HTM 02-01 also lists backfeed kits used by engineering staff among the tertiary sources of supply. During emergencies or planned shutdowns, trained engineering staff may backfeed through a NIST connector or a terminal unit, with backfeed kits of at least two cylinders, one on each bank, managed under a permit-to-work scheme. HTM 02-01 asks for NIST connections on all line valve assemblies and [area valve](https://library.ultracontrolo.com/glossary/area-valve/) service units.

For areas that need resilience beyond the three standard sources, HTM 02-01 also describes a critical emergency supply: a manifold upstream of the area valve that feeds the zone through a non-return valve and should start automatically when the primary, secondary and tertiary sources fail. The ULTRAGEC emergency cabinet from Ultra Controlo connects by derivation to the secondary network upstream of a critical area, and the Ultra Controlo range includes a maintenance supply assembly for temporary gas delivery during pipeline servicing.

## Sources

- [HTM 02-01 (2026) Part A, paragraphs 3.53, 5.80 to 5.84 and 6.93 to 6.97 (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)
- [ULTRAGEC datasheet, p. 2](https://www.ultracontrolo.com/products/ultragec)
- [Ultra Controlo, maintenance supply assembly (accessories)](https://www.ultracontrolo.com/accessories/maintenance-supply-assembly)

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