Facilities maintenance glossary

01

Planned preventive maintenance (PPM)

Also called: Planned maintenance, Preventive maintenance

Maintenance carried out on a schedule to stop equipment failing, rather than after it has failed. In facilities management, PPM covers servicing, inspections and statutory tests on plant such as air conditioning, boilers, fire alarms and emergency lighting, usually under a maintenance contract that sets what is done and how often.

Planned maintenance software How to build a PPM schedule

02

PPM schedule

The list of every asset on each site, the maintenance tasks each one needs, how often each task is due, and when each visit is booked. For a contractor it defines what a maintenance contract covers and what engineers do on each visit.

How to build a PPM schedule Planned maintenance software

03

Reactive maintenance

Also called: Call-out, Breakdown maintenance

Maintenance carried out in response to a fault or request, such as a leak, a failed unit or a fire panel fault, rather than on a schedule. Reactive jobs usually have a response time set by the contract, and are often where jobs get missed, run late or never get invoiced.

Reactive maintenance scheduling software

04

SLA (service level agreement)

Also called: Attend-by time, Response time

The part of a maintenance contract that sets how quickly the contractor must respond and fix a fault, usually by priority: for example, attend within four hours for an emergency and within a set number of days for a routine fault. Missing SLAs can cost a contractor penalties or the contract at renewal.

Reactive maintenance scheduling software

05

Remedial works

Also called: Remedials

Repairs or replacements found to be needed during a planned visit or inspection, such as a failed emergency light battery or a worn pump, and quoted to the client as extra work outside the maintenance contract. Remedials are often the most profitable work a maintenance contractor does, and the easiest to lose if the fault is not quoted promptly.

Remedial works quoting software

06

Asset register

A record of every piece of equipment a contractor maintains, by site and location, with details such as make, model, serial number and, for refrigeration and air conditioning, the refrigerant and charge. Linking each visit and fault to the asset gives a full service history per unit.

Asset register software

07

Job sheet

Also called: Service sheet, Worksheet

The record an engineer completes on a job: what was done, readings, photos, parts used and the customer's signature. A signed job sheet is the evidence the work was done and is usually what an invoice is raised from.

Job sheet app Job invoicing software

08

RAMS (risk assessment and method statement)

A risk assessment sets out the hazards of a job and how they are controlled; a method statement sets out step by step how the work will be done safely. A risk assessment is a legal requirement under the Management of Health and Safety at Work Regulations 1999. A method statement is not specifically required by law, but clients commonly ask for both before work starts on their site.

Source: CHAS, What is a method statement?

RAMS software

09

SFG20

The UK industry standard for building maintenance specification: a library of maintenance schedules setting out the tasks and frequencies for each type of building services asset. It was created by BESA (the Building Engineering Services Association) and is now maintained by SFG20 Ltd. Many FM clients specify SFG20 in their maintenance contracts.

Source: SFG20, What is SFG20?

How to build a PPM schedule

10

F-gas

Also called: Fluorinated greenhouse gas, HFC refrigerant

Fluorinated greenhouse gases, including the HFC refrigerants used in most air conditioning, refrigeration and heat pump systems, such as R410A, R32 and R134a. In Great Britain their use, leak checking, servicing and record keeping are controlled by the F-gas Regulation, and anyone working on this equipment must hold an F-gas qualification.

Source: GOV.UK, Checking F gas equipment for leaks

F-gas leak check frequency For HVAC contractors

11

tCO2e (tonnes of CO2 equivalent)

Also called: CO2 equivalent

A system's refrigerant charge expressed as its climate impact: the charge in kilograms multiplied by the refrigerant's global warming potential, divided by 1,000. F-gas leak check frequencies are set in tCO2e, starting at 5 tCO2e, which is about 2.4 kg of R410A or 7.4 kg of R32.

Source: GOV.UK, Checking F gas equipment for leaks

F-gas leak check frequency

12

GWP (global warming potential)

How much a gas warms the climate compared with the same mass of carbon dioxide, which has a GWP of 1. R410A has a GWP of 2,088 and R32 of 675, so the same charge of R32 counts for about a third as much under the F-gas rules.

F-gas leak check frequency

13

F-gas leak check

A check of refrigeration, air conditioning or heat pump equipment for refrigerant leaks, required by law at intervals set by the charge: at least every 12 months from 5 tCO2e, every 6 months from 50 tCO2e, and with automatic leak detection required from 500 tCO2e. Records of each check must be kept for at least five years.

Source: NetRegs, F-gas controls for refrigeration and air conditioning

F-gas leak check frequency

14

BS 5839-1

The British Standard for fire detection and fire alarm systems in non-domestic buildings. It recommends that systems are inspected and serviced by a competent person at intervals of no more than six months, alongside weekly tests by the building's occupier.

Source: Cherwell District Council, fire alarm and emergency lighting testing

Fire alarm maintenance software

15

BS 5266-1

The British Standard for emergency lighting. It sets out a short functional test each month and an annual full-duration test, in which the lights must run on battery for their rated duration, typically three hours, with records kept of each test.

Source: Fire Protection Association, How to test emergency lighting

Fire alarm maintenance software

16

Subcontractor compliance

Checking that the subcontractors a contractor sends to a client's site are insured, qualified and accredited for the work: for example public liability insurance, F-gas certificates and trade accreditations, each with an expiry date to track. A lapse puts the contractor, not just the subcontractor, at risk with the client.

Subcontractor management software

17

PO number (purchase order)

The reference a client issues to authorise a job and commit to paying for it. Many FM clients will not pay an invoice without a valid PO number on it, so a job that is finished but has no PO is money a contractor cannot yet invoice.

Job invoicing software

18

CAFM (computer-aided facilities management)

Software used to manage buildings and the work done on them: assets, planned and reactive maintenance, space and property records. The term usually refers to systems used by a building owner's FM team; the software a maintenance contractor runs its own jobs, engineers and invoicing on is more often called job management or field service management software.

Facilities management software for contractors

19

Field service management (FSM)

Software and processes for running work done at customers' sites: taking requests, scheduling engineers, job sheets on mobile devices, and invoicing. AI field service management software adds automation such as drafting jobs from emails and invoices from completed job sheets.

AI field service management software

20

Job management software

Software that runs a contractor's jobs from request to invoice: logging jobs, scheduling engineers, job sheets, quotes and invoicing, often with planned maintenance and asset records. In the UK the term is used mostly by trade and maintenance contractors.

Best job management software UK Job management software cost

Definitions checked 4 November 2026. If one is wrong or out of date, tell us.