Types of Sprinkler Heads: Complete Guide for Fire Protection Engineers

The Importance of Proper Sprinkler Head Selection

The sprinkler head is the heart of every sprinkler system. It detects fire through its thermal element and releases water in the appropriate spray pattern. Selecting the wrong sprinkler type can lead to ineffective protection, commissioning issues, or unnecessary costs.

At Oskar Sprinkler, installing sprinkler systems across Belgium, the Netherlands, Norway, and Germany, we work daily with various sprinkler types. In this guide, we share practical knowledge about their applications.

Sprinkler Head Classification

By Mounting Orientation

• Pendent — mounted with deflector facing down, most common in spaces with suspended ceilings
• Upright — mounted with deflector facing up, typical for industrial halls and warehouses
• Sidewall — wall-mounted, spraying in one direction, ideal for corridors and small rooms
• Concealed — with decorative cover plate, used in buildings with high aesthetic requirements

By Activation Temperature

• 57°C (orange) — standard for most rooms
• 68°C (red) — most commonly used type
• 79°C (yellow) — for rooms with elevated temperatures
• 93°C (green) — boiler rooms, drying rooms
• 141°C (blue) — very high ambient temperature areas
• 182-260°C — special industrial applications

The activation temperature must account for maximum ambient temperature — the sprinkler should be rated at least 30°C above the expected maximum ceiling temperature.

By K-Factor (Flow Coefficient)

• K57 (K5.6) — standard sprinkler for LH and OH applications
• K80 (K8.0) — enhanced output for OH and HH
• K115 (K11.2) — high output for warehouse applications
• K160 (K16.0) — ESFR for high-bay warehouse protection
• K200 (K19.6) — highest output ESFR
• K360 (K25.2) — special ESFR sprinklers

ESFR Sprinklers — A Revolution in Warehouse Protection

ESFR (Early Suppression, Fast Response) sprinklers changed the approach to high-bay warehouse protection. Unlike traditional sprinklers that control a fire until the fire brigade arrives, ESFR sprinklers are designed for fire suppression — generating sufficient water flow to extinguish the fire at an early stage.

ESFR Advantages

• Elimination of in-rack sprinklers in many configurations
• Reduced installation costs — fewer sprinklers, less piping
• Greater warehouse layout flexibility — no restrictions from in-rack sprinklers
• Faster response through fast-response thermal elements

ESFR Limitations

• High water supply demands (pressure and flow)
• Limitations on maximum storage height and commodity types
• Clearance requirements below ceiling
• Not all warehouse configurations are suitable for ESFR

Read more about ESFR vs. CMSA system comparison in our article on warehouse sprinkler systems.

Specialty Sprinklers

Dry Sprinklers (Dry Pendent/Upright)

Used in wet systems where the sprinkler must be mounted in a freeze-prone zone (e.g., cold storage facilities, loading docks). Water does not enter the portion of the sprinkler in the freezing zone.

Corrosion-Resistant Sprinklers

With protective coatings (wax, PTFE, special lacquers) for use in chemically aggressive environments, cold storage, or high-humidity facilities.

Decorative and Concealed Sprinklers

With ceiling-matched cover plates, flush mount or recessed — for hotels, offices, retail spaces, and anywhere aesthetics matter.

Window Sprinklers

Special sprinklers for protecting glazed facades, creating a water curtain instead of a traditional spray pattern.

Open Sprinklers (Deluge)

Without a thermal element — permanently open, activated by an external detection system. Used in deluge systems for very high-risk areas.

Thermal Elements

Two main types of thermal elements:

• Glass bulb — filled with liquid that expands under heat and shatters the bulb. Colors correspond to activation temperatures.
• Fusible link — metal element soldered with an alloy of known melting point. Often used in industrial sprinklers.

Response Speed

• Standard Response — typical response time for most applications
• Fast Response — faster response due to lower thermal mass, required in some applications (LH, ESFR)
• RTI (Response Time Index) — parameter defining response speed: below 50 = fast response, above 80 = standard response

Selection Criteria

When choosing a sprinkler, consider:

• Hazard classification — determines required K-factor and spray density
• Room height — affects sprinkler type and output
• Ambient temperature — determines activation temperature and potential need for dry sprinklers
• Aesthetics — public buildings may require concealed or decorative sprinklers
• Environment — corrosion, humidity, chemically aggressive substances
• System type — wet, dry, pre-action — influences sprinkler selection

Certifications and Approvals

• VdS — German certification institute, recognized across Europe
• LPCB — British equivalent
• FM Approved — American standard, often required by international insurers
• UL Listed — another American standard

Common Installation Mistakes

• Wrong orientation — pendent sprinkler mounted as upright or vice versa
• Wrong temperature — 68°C sprinkler in a room exceeding 38°C ambient
• Painted sprinklers — paint on the bulb or fusible link
• Wrong ceiling distance — outside manufacturer's tolerance range
• Missing guards — in areas exposed to mechanical damage

Conclusion

Proper sprinkler head selection is one of the most important elements of sprinkler system design and installation. It requires knowledge of standards, facility conditions, and manufacturer offerings. At Oskar Sprinkler, we help our clients select optimal solutions for every project.

Have questions about sprinkler selection? Contact us — we will help you choose the best solution.