Wired vs wireless medical gas alarm systems

That NFPA 99 text does not use the word wireless; it speaks of communication by means other than wires and of communication devices that do not use electrical wiring for signal transmission. In that report the text is shown struck through under committee input CI-1071, with the committee's statement that further review of the alarm requirements of section 5.1.9 was needed; NFPA now lists the 2027 edition of NFPA 99 as current, so check the edition and text that apply to your project.

Wires and other means in the NFPA 99 2021 text

The same text also covers:

• visual and audible indication, on all master, area and local alarm systems, that the communication with an alarm-initiating device is disconnected
• master alarm panels that communicate directly to the alarm-initiating devices they monitor, with no relaying of master alarm signals from one master alarm panel to another
• for wires only: where initiating devices are remote from the building and the wiring runs underground in compliance with NFPA 70, the wiring is permitted to run to a junction box where it first enters the building, with a single set of wires for each signal between the initiating device and the junction box

NHS England and NHS Scotland guidance

The warning and alarm chapter of HTM 02-01 Part A (2026), the NHS England guidance, does not mention wireless links. It lists among the functional elements of warning and alarm systems interfaces and transmitters that convert the signal from plant or manifold volt-free alarm contacts into a form which can be transmitted via multiplexed cable which includes line contact monitoring, and interconnecting multiplex wiring which connects all interfaces and transmitters to all indicator panels (14.66). It also says:

• the system should monitor the integrity of the lines between the initiating devices and the panel or transmitter units, and should indicate a system fault on loss of data transmission between panels and transmitters (14.33, 14.35)
• where multi-core cabling is used, the alarm cables should be dedicated to the medical gas alarm systems only, and the system should be designed to reject spurious radio frequency interference and electrical noise (14.16, 14.17)
• medical gas alarms should be a stand-alone alarm system but may be mirrored to other devices for monitoring purposes only (14.1)

SHTM 02-01 Part A (Version 2, August 2026), the guidance for Scotland, lists the same functional elements, including interconnecting multiplex wiring to all indicator panels (10.9). For medical oxygen cylinder auto-change manifolds and liquid cylinder or mini tank installations supplied with a human machine interface display, it says these integrated systems are required to provide the outputs for connection to the healthcare facility alarm system and that these alarm outputs must be failsafe and hard-wired (5.237).