Lifts should not be used in a fire unless they are designed for it, which leaves anybody who cannot use stairs waiting in a refuge for help. An evacuation chair is one way that help arrives. Buying one is easy and is the least important part: the plan, the trained people and the communication are what actually get somebody down the stairs.
The plan comes first
A personal emergency evacuation plan is written for a named individual who needs assistance, and it says where they go, who assists, how they are summoned, by what route, and what happens if the assistants are absent that day. For visitors and members of the public, a general emergency evacuation plan covers the same ground without knowing who will need it. The chair is equipment that plan may or may not call for.
Refuges and communication
A refuge is a relatively safe place, usually a protected stair landing, where somebody can wait. A refuge without a working way to tell anybody you are in it is a waiting room. Two way communication systems linked to the fire alarm panel or a manned point are what make a refuge part of a strategy, and testing them belongs with the alarm testing rather than being nobody's job.
Training the operators
Taking a person down a staircase in a chair is a skill and it is not obvious. Operators need training, refreshed, and there need to be enough of them that a holiday or a sick day does not empty the plan. Buildings frequently have a chair on a landing and nobody currently trained, which is the most common finding in this area and the easiest to fix.
Servicing and hire
Chairs are mechanical equipment with tracks, belts, brakes and moving parts that need periodic inspection and servicing, and manufacturers specify an interval. Hire is common for events and temporary needs, and a hired chair should arrive with current service records and with training arranged, not just with the chair. Either way it is equipment under the general duty to maintain.
Questions people ask about evac chair servicing
Does my building need an evacuation chair?
That comes out of the evacuation plans for people who cannot use stairs. Some buildings meet the need through evacuation lifts, refuges and fire service assistance, others through chairs and trained operators.
Who can use an evacuation chair?
Trained operators, with enough of them that absence does not defeat the plan. A chair on a landing with nobody currently trained is the most common finding in this area.
How often should an evac chair be serviced?
To the manufacturer's specified interval, as mechanical equipment with tracks, brakes and moving parts. It falls under the general duty to maintain fire safety equipment in working order.