FPAS Fire Systems Design (FSD) flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Alarm zone

A defined area of a fire detection system that is separately annunciated at the control panel so responders can locate the alarm source.

Smoke detector spacing

Smoke detector coverage is limited by listed spacing, ceiling height, beams, and airflow; manufacturers specify maximum area and distance between detectors.

Alarm audibility requirement

Fire alarm sounders must produce at least 65 dBA at occupied locations or 5 dBA above ambient, and commonly 75 dBA at sleeping-area bedheads.

Battery standby calculation

Secondary battery capacity equals standby current times standby hours plus alarm current times alarm hours, typically 24 hours standby and 5 minutes alarm, with derating.

End-of-line resistor

A supervised detection circuit uses an end-of-line resistor so the panel can detect open circuits, short circuits, and device removal as distinct fault conditions.

Cross-zoning

A logic arrangement requiring alarms from two independent detectors or zones before a suppression release or high-level alarm, reducing false activation.

Heat detector suitability

Heat detectors suit dusty, smoky, or cooking environments where smoke detectors would false-alarm, but they respond more slowly to smouldering fires.

Design density formula

Minimum sprinkler flow equals design density multiplied by the design area of operation, with density in mm/min and area in square metres giving litres per minute.

Sprinkler K-factor formula

For metric K-factors, sprinkler flow in litres per minute equals the K-factor multiplied by the square root of pressure in bar.

Ordinary sprinkler rating

A 68°C rated sprinkler is common for ordinary occupied spaces; the rating must exceed the maximum ambient temperature and suit the ceiling environment.

Inspector's test valve

A test connection at the hydraulically most remote point that simulates one sprinkler flowing, verifying alarm valve and flow-switch operation.

Hazen-Williams formula

Friction loss in water pipes is calculated as h = 10.67 L Q^1.85 / (C^1.85 d^4.87), using consistent SI units.

Main drain test

A main drain test records static and residual pressure to indicate supply valve status and detect deterioration in the water supply.

Wet-pipe alarm valve

A wet-pipe alarm valve controls water flow into a sprinkler system and initiates an alarm when a sprinkler operates and creates sustained flow.

Hydrant residual pressure

The pressure remaining at a flowing hydrant after elevation and friction losses; it must meet the code minimum at the most remote design hydrant.

Fire brigade booster

A connection allowing fire service pumpers to supplement the hydrant or sprinkler supply; it must be accessible, marked, and compatible with brigade couplings.

Hose reel coverage

A hose reel must reach all parts of its protected area with a 30 m hose, allowing for hose route, obstructions, and doorways without passing through fire doors.

Hydrant ring main

A looped water main supplying hydrants from more than one direction, improving reliability and reducing pressure loss compared with a dead-end main.

Sectional isolating valve

A valve that isolates part of a hydrant ring main for maintenance while keeping the remaining hydrants in service; placement limits the number isolated.

Hydrant flow test

A test recording static pressure, residual pressure, and flow rate at a hydrant to verify that the supply meets the design demand.

Total-flooding agent mass

Agent mass equals enclosure volume divided by specific volume, multiplied by design concentration divided by 100 minus concentration.

NOAEL

No-observed-adverse-effect level; the highest agent concentration at which no adverse health effect is expected, used to set limits for occupied spaces.

Enclosure integrity test

A door-fan test that measures room leakage and predicts whether the enclosure will hold the design agent concentration for the required hold time.

Clean-agent discharge time

Total-flooding clean-agent systems typically discharge within 10 seconds, while inert-gas systems often use 60 to 120 seconds to control pressure and noise.

CO2 occupancy hazard

Carbon dioxide total-flooding systems are not permitted in normally occupied spaces because discharge can cause rapid asphyxiation; they suit unoccupied hazards.

Pre-discharge delay

A timed interval after alarm confirmation before agent release, allowing occupants to evacuate and responders to investigate or abort the discharge.

Extinguisher rating code

A label such as 2A:10B:C shows the Class A water-equivalent rating, Class B test-fire size, and Class C electrical non-conductivity.

Class F wet chemical

Wet chemical extinguishers saponify hot cooking oils, forming a soap-like layer that cools and seals the surface, making them suitable for Class F fires.

CO2 extinguisher limitation

CO2 extinguishers are effective on electrical fires but provide little cooling and can displace oxygen in confined spaces, creating an asphyxiation risk.

Class D metal fire

Class D fires involve combustible metals such as magnesium or sodium; special dry powders are required because water, foam, and CO2 can react violently.

Extinguisher mounting height

Portable extinguishers are mounted so the carrying handle is not more than 1.5 m above the floor, with the label visible and the unit accessible.

Dry powder residue

Dry-powder extinguishers leave corrosive or insulating residue that can damage electronics and machinery; clean-agent extinguishers are preferred for sensitive equipment.