Explore The Different Fire Sprinkler Ordinary Hazard (OH) Groups
Most commercial and industrial buildings fall within the Ordinary Hazard classification under BS EN 12845.
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These systems are designed to protect environments with moderate fire risks, such as offices, retail spaces, schools, and light manufacturing facilities.
OH1
Ordinary Hazard group 1
Low fire load and slow rate of fire spread. Suitable for light to moderate risk environments where combustibles are limited.
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Offices, hotels, schools, hospitals, restaurants...
OH2
Ordinary Hazard Group 2
Moderate fire load and expected fire growth. Common in general commercial and public-access premises.
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Retail stores, car parks, light manufacturing areas...
OH3
Ordinary Hazard Group 4
Higher fire load and faster potential fire development. Requires greater water discharge for effective protection.
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Workshops, packaging facilities, distribution areas...
OH4
Ordinary Hazard group 4
Very high fire load and rapid fire spread potential. Demands the highest level of sprinkler performance within the Ordinary Hazard range.
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Printing facilities, automotive workshops, paper or textile processing...
