Fire strategy changes fundamentally in a high-rise because two assumptions collapse: that the whole building can be emptied quickly, and that the fire service can intervene from outside. In their place come defend-in-place and internal attack.
Classification
BYKHY defines a high-rise as a building with a building height above 21.50 m or a total height above 30.50 m. Because the classification determines which provisions apply, how levels and heights are measured must be settled at the very start of the project; for a building near the threshold that single decision changes the whole design.
Six headings that change
1. Escape strategy
Phased evacuation replaces total evacuation: the fire floor and adjacent floors are cleared first. That requires the voice alarm system to be manageable zone by zone.
2. Protected stairs and pressurisation
The stair enclosure must stay clear of smoke. The pressurisation system has to satisfy different operating points with doors open and closed, so the design follows door-opening scenarios and door opening force is measured at commissioning.
3. Firefighting lift and bridgehead
A dedicated lift with standby supply and a protected lobby is needed so firefighters can reach upper floors with equipment. Attack is made through risers fed from the fire brigade connection.
4. Fire control centre
The alarm panel, smoke control commands, pump status, lift positions and the public address system are monitored from one point. This is the first place the fire service goes on entering the building; its accessibility and protection are part of the design.
5. Pressure zones
The sprinkler installation is divided into vertical zones so the pressure rating of pipe and components is not exceeded. Each zone has its own control valve, flow switch and test-and-drain arrangement. Where pressure reducing valves are used, the topmost sprinkler receiving its required pressure and the lowest not exceeding its limit must be achieved at the same time.
6. Water supply redundancy
A single pump and a single tank are not considered adequate in a high-rise. Intermediate tanks, a standby pump, a second supply line and independent power supplies to the pumps are typical requirements. The additional reliability measures in EN 12845 and the standby pump provisions in NFPA 20 are the texts to consult.
A common mistake: setting zone boundaries by hydraulics alone. A zone boundary is also a maintenance and isolation boundary. If maintaining one zone requires taking half the building out of service, the zoning is wrong.
Critical commissioning tests
- A flow test from the most remote sprinkler point in every pressure zone.
- Door force and air velocity measurement on the pressurisation system.
- The standby pump start scenario.
- Testing the phased evacuation scenario together with the public address system.
- Operation of the firefighting lift on standby supply.
- Verification that every system can be monitored from the fire control centre.
Frequently Asked Questions
How is a high-rise defined?
BYKHY defines it as a building with a building height above 21.50 m or a total height above 30.50 m. For buildings near the threshold, the measurement method affects the whole design.
What sets the pressure zones?
The pressure rating of pipe and components — but a zone boundary is also a maintenance and isolation boundary. If maintaining one zone shuts half the building, the zoning is wrong.
What is the evacuation strategy in a high-rise?
Phased evacuation rather than total evacuation. The fire floor and adjacent floors are cleared first, which requires zone-by-zone control of the voice alarm.
What redundancy is expected in the water supply?
Intermediate tanks, a standby pump, a second supply line and independent power supplies to the pumps. The EN 12845 additional reliability measures and NFPA 20 standby pump provisions are the references.
SprinkCalc — Fire Sprinkler Design Across Three Standards
SprinkCalc covers hazard classification, design density and area, K-factor selection, water demand and hydraulic calculations for NFPA 13, FM Global and BS EN 12845 in a single iOS app, and exports a professional PDF report.
Download SprinkCalc on the App Store
MEP Calc — 86+ Engineering Calculators
MEP Calc bundles 86+ engineering modules in one iOS app: 21 fire calculations plus heating, cooling, HVAC, plumbing, steam and natural gas.
Download MEP Calc on the App StoreThe Turkish Regulation on Fire Protection of Buildings (BYKHY) · NFPA 13 (2025) · NFPA 20 (2025) · BS EN 12845:2015+A1:2019 · FM Global Data Sheets. For article numbers, thresholds and exemptions, the current regulation text published in the Official Gazette governs.