The short answer: BYKHY defines which buildings need sprinklers (Article 96(2)) and requires sprinkler system design to be carried out to TS EN 12845 (Article 96(5)). NFPA 13 is used only as an additional layer, when an insurer, investor or international specification asks for it, and on condition that the minimum requirements of the regulation are met; the calculations of the two standards are not mixed.
The role of the regulation
The Regulation on Fire Protection of Buildings is the framework instrument for fire safety in Turkey. Its scope is broad: escape routes, fire compartmentation, smoke control, detection and alarm, suppression systems, fire safety management. Annex 8/B gives design density and area values for the preliminary water-storage calculation (Article 92(5)). For sprinkler design, however, the regulation does not leave the choice of standard to the designer: under Article 96(5), sprinkler system design is to be carried out to TS EN 12845. The same paragraph states that in Light Hazard and Ordinary Hazard Group 1 occupancies one standard sprinkler may be positioned to protect at most 21 m². Article 96(1) also requires system components to comply with TS EN 12259.
The regulation says what is required; for sprinklers, the standard it names, TS EN 12845, says how it is done. Detailed hydraulic calculation and spacing rules come from that standard. The route to internationally recognised standards in Article 5(2) is open only for matters not covered by Turkish or European standards; it does not make NFPA 13 an alternative that replaces TS EN 12845 for sprinkler design.
Is an additional layer needed?
In Turkey the regulatory baseline is TS EN 12845. The real question is whether an additional layer such as NFPA 13 or FM Global is needed on top of it. Four inputs decide that:
- The approving authority. The authority checks compliance with the regulation; whatever additional layer is used, the approval file must demonstrate compliance with TS EN 12845.
- Insurer requirements. International insurers frequently ask for FM Global or NFPA-based design, and that requirement sits on top of the regulation, not in place of it.
- Investor or corporate standard. A multinational manufacturer applies one standard across all its plants; at the Turkish plant that standard is applied as an additional layer, on condition that the minimum requirements of the regulation are met.
- The equipment supply chain. On the regulatory side, all equipment used in the system must be certified (Article 90(3)) and sprinkler system components must comply with TS EN 12259 (Article 96(1)). If the additional layer asks for UL/FM listing, the equipment must satisfy both requirements; availability and cost differ between UL/FM listed equipment and LPCB/VdS approved equipment.
The golden rule: each calculation within one standard, end to end. Taking the design density from EN 12845 and the area of operation from NFPA 13 is an engineering error. The numbers in each standard assume one another; mixed, they produce a system carrying neither one's safety margin. Where there is an additional layer, a separate and complete check is made against each standard and the more restrictive result governs at every point.
Practical differences at a glance
| Topic | NFPA 13 | EN 12845 |
|---|---|---|
| Hazard class language | Light / Ordinary 1-2 / Extra 1-2 plus storage | LH / OH1-4 / HHP1-4 / HHS |
| Density unit | gpm/ft² (SI equivalent in mm/min, in parentheses) | mm/min |
| Water supply duration | By hazard class | By hazard class, with different values |
| Equipment approval | UL / FM listing | EN 12259 series, LPCB / VdS approval |
| Pump standard | NFPA 20 | EN 12845's own pump section |
| Role under BYKHY | Additional layer (insurer, investor, international specification) | Mandatory design standard (TS EN 12845, Article 96(5)) |
Can all three coexist?
Yes, but in layers: the regulation sets the mandatory floor and names TS EN 12845 for sprinkler design; NFPA 13 or an insurer's FM Global requirement adds a further layer of protection. In that case the design follows the most restrictive requirement, and the design report states explicitly which decision came from which document.
What the design report must state
- The design standard (TS EN 12845, Article 96(5)) and its edition year; where applicable, the additional-layer standard and edition year (for example "NFPA 13, 2025 edition").
- The hazard classification and its justification.
- Design density and area of operation, with the table reference in the standard.
- Water supply duration and the volume calculation.
- Any insurer or investor requirements and which decisions they changed.
- Equipment compliance (TS EN 12259, Article 96(1)) and any additional approval scheme (UL/FM or LPCB/VdS).
Those are the six headings asked about most at review; a report written around them from the start shortens approval noticeably.
Frequently Asked Questions
Does BYKHY contain the sprinkler calculation?
It does not contain the detailed calculation, but it does specify which standard the calculation follows. The regulation defines which buildings need sprinklers (Article 96(2)), gives design density and area values for the preliminary water-storage calculation in Annex 8/B (Article 92(5)) and requires sprinkler system design to be carried out to TS EN 12845 (Article 96(5)). Detailed hydraulic calculation and spacing rules come from that standard; system components must comply with TS EN 12259 (Article 96(1)).
Can a sprinkler project in Turkey be designed to NFPA 13 alone?
No. Article 96(5) requires the design to be carried out to TS EN 12845. NFPA 13 can be used as an additional layer when an insurer, investor or international specification requires it, and even then the minimum requirements of the regulation must be met. The route to international standards in Article 5(2) is open only for matters not covered by Turkish or European standards.
Can NFPA 13 and EN 12845 be mixed?
No. The numbers in each standard assume one another. Taking the density from one and the area of operation from the other produces a system carrying neither one's safety margin.
Does an insurer requirement replace the regulation?
No, it sits on top of it. The regulation is the mandatory floor; an insurer requirement such as FM Global is an additional layer. The design follows the most restrictive requirement.
What decides whether an additional standard layer is needed?
The design standard is fixed by the regulation (TS EN 12845, Article 96(5)). Whether an additional layer such as NFPA 13 or FM Global is needed is decided by insurer requirements, the investor or corporate standard, any international specification and the equipment supply chain, assessed together.
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Download MEP Calc on the App StoreThe Turkish Regulation on Fire Protection of Buildings (BYKHY; articles used: 5(2), 92(5), 96(1), 96(2), 96(5)) · TS EN 12259 · NFPA 13 (2025) · NFPA 20 (2025) · TS EN 12845+A2:2026 · FM Global Data Sheets. For article numbers and numerical limits, the current regulation text published in the Official Gazette governs.