SONA Electronics SM-SN-1 - Page 6

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SYSTEM GRADES AND CATEGORIES
The mains powered SONA™ alarms with 10 year life are suitable for Grade D systems. It is important
to determine the correct alarm system grade and category for the dwelling prior to installation.
A Grade D system is required for:
• New or materially altered dwellings, up to three storeys with no oor exceeding 200 m
2
.
• Existing dwellings with poor or inadequate re protection, up to three storeys with no oor
exceeding 200 m
2
.
• Individual dwelling units of two or more rooms in Houses in Multiple Occupation (HMOs) of one
or two-storeys, with no oor exceeding 200 m
2
.
There are three Levels of Detection (LD). Generally the greater the re risk the more comprehensive
the system should be.
LD1 = Maximum Protection. Alarms in all circulation spaces that form part of escape routes and all
areas where a re might start.
LD2 = Medium Protection. All circulation spaces and escape routes (e.g. hallways and landings) are
covered together with a provision of higher re risk areas (e.g. kitchen and living rooms).
LD3 = Minimum Protection. Alarms in all circulation spaces that form part of escape routes.
* Ensure that a Grade D system is adequate for the dwelling you are installing the alarms in.