Fire safety in Houses in Multiple Occupation (HMOs) is one of the most important responsibilities for landlords and property managers. Whether you operate a small shared house or a large multi-storey HMO, understanding the difference between Grade A and Grade D fire alarm systems is essential for compliance, tenant safety, and successful licence approval. In this guide, we break down the key differences, legal expectations, and best practices to help you choose the right fire safety grade for your HMO.
What Is Fire Safety Grading in HMOs?
Fire alarm grades—such as Grade A and Grade D—are classifications defined under BS 5839, the British Standard for fire detection and alarm systems. These grades help determine the type of alarm system required based on the size, layout, and risk level of your HMO. Local authorities and licensing schemes refer to these grades to ensure that all HMOs meet a consistent and enforceable safety standard.
What Is a Grade A Fire Alarm System?
A Grade A fire alarm system is the highest standard typically required in large or high-risk HMOs. This system includes:
- A central fire alarm control panel
- Smoke and heat detectors
- Manual call points (break-glass units)
- Wired detection circuits with fault monitoring
- Backup power supplies
Grade A systems are designed to provide fast, reliable detection and are capable of supporting multiple zones. These systems are usually required in:
- HMOs of three or more storeys
- Buildings with five or more residents
- Complex layouts that require zoned alarms
- Properties where evacuation may be more challenging
Because they offer advanced monitoring, Grade A systems are also preferred by many local councils for higher-risk or larger HMOs.
What Is a Grade D Fire Alarm System?
A Grade D fire alarm system is more commonly installed in smaller, lower-risk HMOs. These alarms consist of:
- Mains-powered smoke and heat alarms
- Built-in battery backup
- Interlinked alarms (radio-interlinked or hard-wired)
Grade D alarms do not require a central control panel. Instead, the alarms communicate with each other so that if one activates, all interconnected alarms sound simultaneously. Grade D systems are usually suitable for:
- Two-storey HMOs
- Shared houses with 3–4 tenants
- Properties with simple escape routes
While easier to install and maintain, Grade D systems must still meet all HMO licensing conditions and be regularly tested.
Grade A vs Grade D HMOs: Which Do You Need?
The correct fire safety grade depends on factors like the number of occupants, the building’s layout, and your local council’s HMO licensing policy. Generally:
- Small HMOs → Grade D
- Medium to large HMOs → Grade A
Always check your council’s HMO guidelines, as some authorities may require Grade A systems even in smaller properties.
Final Thoughts
Choosing between Grade A and Grade D fire alarm systems is essential for legal compliance and tenant protection in HMOs. By understanding the differences and selecting the grade suited to your property size and risk level, you ensure safety, meet licensing standards, and create a safer living environment for your tenants.