A fire sprinkler system is a network of water-filled pipes fitted with heat-activated sprinklers that open one by one over a fire to control or extinguish it and raise the alarm. In the National Fire Protection Association (NFPA) 2026 report on US fires, sprinklers operated in 90% of fires large enough to activate them and were effective in 97% of those. This owner’s guide covers how they work, where they are required, the main types and upkeep.
Key takeaways
- Each sprinkler opens on its own heat: in 76% of US fires where sprinklers operated, only one opened (NFPA, 2020–2024 data).
- A system shut off before the fire was the most common reason sprinklers failed, so valve supervision and upkeep matter as much as design.
- Design starts from the hazard class of each space or, for storage, the commodity and storage height.
- In new light hazard installations, NFPA 13 (2025 edition) requires quick-response, residential, quick-response control mode specific application (CMSA) or early suppression fast response (ESFR) sprinklers.
- In Saudi Arabia, the Saudi Fire Protection Code (SBC 801) and Civil Defense decide where sprinklers are required; NFPA 25 is the usual reference for upkeep, in the edition SBC 801 and Civil Defense set.
In this article
How a sprinkler system works
Water from the supply and fire pump fills the pipes up to closed sprinklers. Each sprinkler is held shut by a heat-sensitive element, usually a liquid-filled glass bulb or a solder link. When fire gases heat the element to its rating, it releases and water sprays over the fire; sprinklers not heated enough stay closed.
As water flows, a flow switch or alarm valve signals the fire alarm panel and the fire pump starts as pressure drops. Water keeps flowing until the control valve is shut, which is why our valves and network components guide matters to owners. NFPA found fire confined to the object or room of origin in 93% of fires with sprinklers present, against 68% with no automatic extinguishing system, and a civilian death rate per fire 90% lower. System types are compared in our wet, dry, pre-action and deluge systems guide.
Hazard classification basics
NFPA 13 classifies each non-storage space as light hazard, ordinary hazard (Groups 1 and 2) or extra hazard (Groups 1 and 2) by the quantity and combustibility of its contents, and the class sets the water density, design area and sprinkler choices. Our NFPA 13 guide describes each class.
The NFPA 13 annex lists, for example, bakeries, laundries, restaurant service areas and mechanical rooms as Ordinary Hazard Group 1, and flammable liquid spraying, plastics manufacturing and diesel fire pump rooms as Extra Hazard Group 2. Storage is classed by commodity, arrangement and height instead, as our warehouse and high-rack storage guide explains.
Classification follows actual contents, not the room name, so a change of use or storage height needs a design review. NFPA 13 requires a sign recording data such as the occupancy classification and maximum planned storage height.
Where sprinklers are required in Saudi buildings
SBC 801 and Civil Defense set where sprinklers are required, and the 2024 Saudi Building Code has been mandatory since 30 June 2025, as our SBC 801 fire protection guide explains. SBC 801 thresholds are not quoted here, but the International Code Council (ICC) states that the 2018 Saudi Building Codes are based on the 2015 I-Codes, so the model text shows the kind of triggers to expect. In the 2015 International Building Code text, as published on ICC Digital Codes, sprinklers are required, among other cases:
- Group A-2 assembly: a fire area over 5,000 sq ft (464.5 m²), an occupant load of 100 or more, or a fire area not on the level of exit discharge.
- Group M mercantile and Group S-1 storage: a fire area over 12,000 sq ft (1,115 m²) or more than three stories above grade plane, or combined fire areas over 24,000 sq ft (2,230 m²).
- Group R residential: throughout all buildings with a Group R fire area.
- Buildings with a story holding 30 or more occupants 55 ft (16.8 m) or more above the lowest fire department vehicle access level.
These are model-code values, not SBC 801 text; confirm the trigger for each building with the consultant against the adopted SBC 801 edition and Civil Defense.
Sprinkler types: orientation, response and temperature
| Type | Typical use | What to check |
|---|---|---|
| Upright | Exposed pipes in plant rooms, car parks and warehouses | Deflector distance below the ceiling |
| Pendent and recessed pendent | Suspended ceilings in offices, malls and hotels | Escutcheon from the same listed assembly |
| Sidewall | Rooms and corridors where pipe runs along a wall | Listed for the hazard and room size |
| Concealed | Architectural ceilings | Cover plates not painted or glued |
| Dry | Freezers and other freezing areas | Listed dry type of the right length |
| ESFR and storage | High-piled and rack storage | Listing limits |
NFPA 13 (2025 edition) requires escutcheons for recessed, flush and concealed sprinklers to be part of the listed assembly. NFPA 25 (2026 edition) requires damaged, corroded, loaded, field-painted, glued or caulked cover plates to be replaced with listed ones, or the whole assembly where the plate is no longer available.
Quick response or standard response?
Response describes how sensitive the thermal element is, measured as its response time index (RTI). A fast-response element operates sooner than a standard one in the same position, although ceiling height, spacing and distance below the ceiling also matter, the NFPA 13 annex notes. Under NFPA 13, quick-response sprinklers also allow a smaller design area in wet systems in light and ordinary hazard spaces with ceilings up to 6.1 m (20 ft), subject to conditions. TYCO Series TY-B, by contrast, is a standard-response, standard-coverage sprinkler.
Temperature rating and bulb color
The bulb color shows the temperature rating. In the TYCO Series TY-B documentation, for example, 57°C (135°F) bulbs are orange, 68°C (155°F) red, 79°C (175°F) yellow, 93°C (200°F) green, 141°C (286°F) blue and 182°C (360°F) mauve. Where maximum ceiling temperatures exceed 38°C (100°F), NFPA 13 requires a rating suited to them, worth checking under hot roofs and in plant rooms in the Saudi summer.
Common sprinkler myths
| Myth | Fact |
|---|---|
| “All the sprinklers go off at once” | Each opens on its own heat; deluge systems with open nozzles are the exception. |
| “Smoke or cooking fumes set them off” | Standard sprinklers respond to heat, not smoke. |
| “Sprinkler water does more damage than the fire” | Water flows only from sprinklers opened near the fire. |
| “Sprinklers replace the fire alarm and kitchen protection” | Sprinklers control fire, the alarm warns occupants early, and kitchen hoods need their own kitchen suppression system. |
Keeping sprinklers ready: maintenance and owner duties
NFPA 25 (2026 edition) requires sprinklers, pipe, hangers and spare sprinklers to be inspected annually from floor level. Samples are tested or sprinklers replaced at 50 years for standard, 25 for most fast-response and 20 for dry sprinklers, then every 10 years; all sprinklers at 75 years and every 5 years after; and every 5 years in harsh environments. Valves, alarms and impairments are in our NFPA 25 guide.
NFPA 13 requires a spare sprinkler cabinet holding every type, orientation and rating installed: at least 6 for facilities with under 300 sprinklers, 12 for 300 to 1,000, and 24 for over 1,000, with the right wrench and a list of what is installed. The 2025 edition also adds a documentation cabinet for the record of completion, shop drawings and as-built drawings, according to the National Fire Sprinkler Association (NFSA) second-draft summary and Second Revision SR-1054.
- Keep control valves open and supervised, with a valve status test after any shutdown.
- Keep storage below the design height and clear of sprinklers.
- Never paint, cover or hang anything from sprinklers or their pipes.
- Keep the spare sprinkler cabinet stocked, with its wrench.
- Have changes of use, storage or ceilings reviewed before work starts.
- Use qualified personnel: under NFPA 13 (2025 edition), they are trained as the authority having jurisdiction (AHJ) accepts, certified by an approved body, or licensed.
- Schedule NFPA 25 inspections and tests, and keep the reports.
Common mistakes and what drives cost
- A temperature rating too low for heat sources or hot roof spaces.
- Quick-response and standard-response sprinklers mixed in one compartment.
- Ducts, lights or ceilings added below sprinklers, or replacements of a different type.
- Storage raised above the design height.
Cost follows the hazard class and area, system type, water supply, pump and tank, sprinkler types and count, ceiling heights, coordination, testing and documentation.
How AZEIDK helps
Through its fire fighting systems solutions, AZEIDK covers automatic sprinkler systems, fire pumps, valves and pipes. Our engineering design and calculations service analyzes the occupancy, sets the design criteria and prepares the required engineering calculations, and we provide Civil Defense approval support.
Brands within our supply scope include TYCO sprinklers, such as Series TY-B, Series DS-1 dry and Royal Flush II concealed, and Victaulic sprinklers, such as the K16.8 ESFR pendent Model V4702 and FL-QR/SW horizontal sidewalls. We recommend verifying each model’s approval in its datasheet.
FAQ
Do all sprinklers go off at once in a fire?
No. Each sprinkler opens when the fire heats its own element, and the rest stay closed. In NFPA data for 2020 to 2024, one sprinkler operated in 76% of fires where sprinklers operated, and five or fewer in 97%. Deluge systems with open nozzles are the exception.
Can smoke or burnt food set off a sprinkler?
A standard sprinkler responds only to heat at its element, not to smoke, which the fire alarm system detects. A strong heat source very close to a low-rated sprinkler could operate it, which is why the rating is matched to the ceiling temperature.
What is the difference between quick-response and standard-response sprinklers?
A quick-response sprinkler has a more sensitive thermal element, so it operates sooner in the same position. NFPA 13 (2025 edition) requires quick-response or other fast types in new light hazard installations, and quick-response sprinklers can allow a smaller design area in wet systems, subject to conditions.
Which buildings need sprinklers in Saudi Arabia?
SBC 801 and Civil Defense decide, by occupancy, area and height. In the international model code behind the 2018 Saudi codes, sprinklers are required, for example, throughout buildings with a Group R (residential) fire area and in larger mercantile and storage buildings. Confirm the trigger with your consultant.
How long do sprinklers last?
NFPA 25 (2026 edition) requires sample testing or replacement at 50 years for standard sprinklers, 25 for most fast-response and 20 for dry sprinklers, then every 10 years (every 5 years once sprinklers reach 75 years), and every 5 years in harsh environments. Damaged, painted or corroded sprinklers are replaced without waiting.
Planning a sprinkler system or reviewing an existing one? Send us your drawings and use and storage data, and our engineers will review the hazard classification, system type and sprinkler selection. Contact the AZEIDK team
