NFPA 13, the Standard for the Installation of Sprinkler Systems, is the main reference for designing and installing automatic sprinkler systems: it classifies the hazard, sets the design approach and hydraulic calculations, and covers system types, sprinkler positioning and acceptance testing. The current edition is 2025. On Saudi projects, the Saudi Fire Protection Code (SBC 801) and Civil Defense set where sprinklers are required and which edition applies.
Key takeaways
- NFPA 13 covers design, installation and acceptance; inspection, testing and maintenance follow NFPA 25, fire pumps NFPA 20 and standpipes NFPA 14.
- Design starts from the occupancy hazard (light, ordinary Groups 1 and 2, extra Groups 1 and 2) or, for storage, from the commodity class and storage arrangement.
- The 2025 edition rewrote the dry pipe rules, added vapor corrosion inhibitor and vacuum systems, introduced supplemental sprinklers, and adds six protection options for storage under ceilings sloped more than 2 in 12.
- Dry and double-interlock pre-action systems need a 30% larger design area, and quick-response reductions apply to wet systems only.
- The edition for a Saudi project is the one SBC 801 and Civil Defense apply, not automatically the latest.
What NFPA 13 covers
Published by the National Fire Protection Association (NFPA), NFPA 13 addresses sprinkler system design approaches, installation and component options for all occupancy types. NFPA also publishes two residential standards: NFPA 13R for apartment buildings and NFPA 13D for one- and two-family dwellings.
NFPA 13 sits within a family of water-based standards: NFPA 20 for fire pumps, NFPA 14 for standpipe and hose systems and NFPA 25 for inspection, testing and maintenance once the system is in service. For system components, see our fire sprinkler systems guide.
How NFPA 13 is organized
These are the chapters of the 2025 edition used most on projects:
| Chapters | What they cover |
|---|---|
| 3 | Definitions, including system and sprinkler types |
| 4 | General requirements, including the owner’s certificate and system area limitations |
| 7 and 8 | Components and system types: dry pipe (8.2), pre-action (8.3) and vacuum systems (8.11) |
| 9 to 14 | Sprinkler location and spacing by sprinkler type, including obstructions, control mode specific application (CMSA) sprinklers (Chapter 13) and early suppression fast response (ESFR) sprinklers (Chapter 14) |
| 16 | Piping installation details, flexible sprinkler hose, the documentation cabinet and signs |
| 19 | Design approaches for non-storage occupancies |
| 20 to 25 | Storage protection, including sloped ceilings (20.9) and in-rack sprinklers (Chapter 25) |
| 28 | Hydraulic calculation rules, such as the pipe friction C-factor |
| 29 | Systems acceptance, including hydrostatic and other acceptance tests |
Annex A gives explanatory material and examples, including example occupancies for each hazard class.
Hazard classification and design approach
For non-storage spaces, NFPA 13 classifies each space by the quantity and combustibility of its contents:
| Classification | What it describes |
|---|---|
| Light hazard | Low quantity and combustibility of contents |
| Ordinary hazard Group 1 | More contents than light hazard, still low combustibility; stockpiles up to 2.4 m (8 ft) |
| Ordinary hazard Group 2 | Larger quantity, higher combustibility; stockpiles up to 3.7 m (12 ft), or 2.4 m for contents with higher heat release rates |
| Extra hazard Group 1 | Very high quantity of combustibles where rapidly spreading fires are possible, such as areas with dust and lint |
| Extra hazard Group 2 | Very high quantity of combustibles with substantial flammable or combustible liquids, or extensive shielding of combustibles |
Storage is designed from the commodity class (Class I to IV, plus plastics), the storage arrangement and the storage height, as our warehouse and high-rack storage guide explains. Hydraulic calculations then size the pipes, the fire pump and the water supply.
The system type changes the numbers too. According to the MeyerFire design area cheat sheet, dry and double-interlock pre-action systems need a 30% larger design area, and quick-response reductions apply only to wet systems in light and ordinary hazard occupancies. In a dry system, water must reach the most remote sprinklers assumed open within a time set by hazard, as our guide to wet, dry, pre-action and deluge systems explains.
Key changes in the 2025 edition
| Change | Where | What it means |
|---|---|---|
| Dry pipe rules rewritten | 8.2 | Section reorganized; water delivery time rules consolidated in 8.2.4; gridded dry systems remain prohibited (8.2.1) |
| Vapor corrosion inhibitor (VCI) and vacuum systems | 8.2.11 and 8.11 | New installation rules with listed equipment; vacuum systems use sprinklers listed for vacuum conditions |
| C-factor of 120 | Chapter 28 | Allowed since 2022 for nitrogen-filled dry systems, now extended to systems with VCI and to vacuum systems |
| Supplemental sprinklers | Chapter 9 and 14.2.10.3.5 | New term for sprinklers below obstructions; quick response; stricter spacing under obstructions for ESFR and CMSA |
| Sloped ceilings in storage | 20.9 | Six protection options above 2 in 12; the ESFR design area can grow from 12 to 18 sprinklers |
| High ceilings, non-storage | 19.2.3.2.5 | Above 9.1 m (30 ft): no sidewall sprinklers from Ordinary Hazard Group 1 up, a minimum K-factor of 11.2 from Group 2 up, and no standard-response sprinklers in Group 2 above 12.2 m |
| Owner’s certificate and documentation | 4.2 and Chapter 16 | Basis of design with a storage plan and water supply data, and a cabinet for completion documents and as-built drawings, per the National Fire Sprinkler Association (NFSA) second-draft summary |
Section numbers come from NFSA and QRFS summaries; confirm them in the published edition.
How NFPA 13 applies on Saudi projects
SBC 801, whose 2024 edition is listed by the Saudi Building Code Center, sets where automatic sprinklers are required together with Civil Defense requirements, and the design follows the NFPA 13 edition named in the project specification. The 2024 edition of the Saudi Building Code has been mandatory since 30 June 2025, as our SBC 801 fire protection guide explains.
The edition that applies is the one SBC 801 and Civil Defense apply, not automatically the latest, so confirm it and state it on the drawings and calculations. Insurers applying FM Global data sheets may add requirements, so identify them early.
In our engineering judgment, most Saudi buildings keep piping above 4°C, so wet systems are the default, while freezers and some unheated spaces in colder regions need dry or pre-action systems.
Applying NFPA 13 on a project: step by step
- Confirm where sprinklers are required under SBC 801 and Civil Defense requirements, and the NFPA 13 edition for the project.
- Classify each space’s hazard, or the commodity and storage arrangement in storage areas, and record it on the drawings.
- Choose the system type for each area: wet by default, dry or pre-action where freezing or water damage risk justifies it.
- Select sprinklers within their listings for response, K-factor, coverage and temperature rating.
- Lay out sprinklers around obstructions, ceiling shapes and storage, coordinated with lighting, ducts and structure.
- Run hydraulic calculations on a recent water supply test, and coordinate the fire pump and tank.
- Submit drawings and calculations for approval, then flush, hydrostatically test and document acceptance.
- Hand over the basis-of-design records and start the NFPA 25 maintenance program.
Acceptance, maintenance and cost
NFPA 13 requires acceptance tests before handover. In the 2022 edition (Sections 29.2.1.1 and 29.2.1.3, as quoted by QRFS on hydrostatic testing), piping is hydrostatically tested at 13.8 bar (200 psi) and held for 2 hours without loss, and portions normally above 10.3 bar (150 psi) are tested at 3.4 bar (50 psi) above working pressure; confirm the clauses in the adopted edition.
After handover, inspection, testing and maintenance follow NFPA 25, now in its 2026 edition. There is no typical system price: cost follows the hazard class, the system type and the hydraulic demand that sizes pipes, pump and tank, plus sprinkler count, installation height, coordination and testing.
Common site mistakes
- Hazard classified from the architectural use name rather than the actual contents.
- Storage raised or packaging changed after design without a new review.
- Hydraulic calculations based on an old or assumed water supply test.
- Lights, ducts or cable trays installed below sprinklers after commissioning.
- A dry system specified where a wet system would work, adding delay and maintenance.
How AZEIDK helps
AZEIDK’s fire fighting systems solutions cover automatic sprinkler systems, fire pumps, valves and pipes, and foam and deluge systems based on project requirements, with supply and installation, testing and commissioning, and maintenance support. Our engineering design and calculations service analyzes the occupancy, sets the design criteria and prepares the required engineering calculations, and Civil Defense approval support supports the approval route.
Our supply scope includes TYCO sprinklers, among them Series TY-B and Series DS-1 dry sprinklers for freeze-prone areas, and we recommend verifying each model’s approval in its datasheet. This draws on 16+ years in the Saudi market.
FAQ
What is NFPA 13 used for?
NFPA 13 sets requirements for designing, installing and accepting automatic sprinkler systems in all occupancy types: hazard classification, choice of system and sprinklers, layout, hydraulic calculations and acceptance tests. Its aim is to deliver the required water to a fire at the required pressure. The current edition is 2025, and a 2028 edition is in development.
Which edition of NFPA 13 applies in Saudi Arabia?
The edition set through SBC 801, Civil Defense requirements and the project specification, not necessarily the latest; publication of the 2025 edition does not make it mandatory automatically. Confirm the edition in writing with the consultant before design, and state it on the drawings and calculations, because the edition changes rules such as dry systems and sloped or high ceilings.
What is the difference between NFPA 13, 13R and 13D?
NFPA 13 covers all occupancy types and offers the most design alternatives. NFPA 13R is for apartment buildings and NFPA 13D for one- and two-family dwellings, with lighter requirements. The adopted code decides when each may be used, and commercial and mixed-use buildings are usually designed to NFPA 13.
How do I determine the hazard classification of a space?
Start from the actual contents, not the use name: their quantity, combustibility, stockpile height and any flammable liquids. Compare them with the NFPA 13 definitions and the Annex A examples, agree the classification with the consultant and record it on the drawings, because a later change in use or storage may require a design review.
What are the main changes in NFPA 13 2025?
The dry pipe rules were reorganized; vapor corrosion inhibitor and vacuum systems got their own rules; sprinklers below obstructions are now supplemental sprinklers, with stricter spacing for ESFR and CMSA; storage under sloped ceilings gained protection options; and ceilings above 9.1 m in non-storage occupancies limit the sprinkler types allowed.
Does NFPA 13 cover sprinkler maintenance?
No. After handover, inspection, testing and maintenance follow NFPA 25, now in its 2026 edition, which sets the frequencies for inspecting and testing valves, sprinklers and piping. NFPA 13 covers design, installation and acceptance testing, including the hydrostatic test before the system is put into service. Later results are compared with the signed acceptance records, so keep them with the basis-of-design documents.
Designing a sprinkler system to NFPA 13? Send us your drawings and use and storage data, and our engineers will review the hazard classification, system type and calculation basis with you. Contact the AZEIDK team
