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The accompanying sketch shows two semi-detached houses - Leaving Cert Construction Studies - Question 9 - 2006
Question 9
The accompanying sketch shows two semi-detached houses. (a) Using notes and freehand sketches, show two design details that would help restrict the spread of fire b... show full transcript
Worked Solution & Example Answer:The accompanying sketch shows two semi-detached houses - Leaving Cert Construction Studies - Question 9 - 2006
Step 1
Using notes and freehand sketches, show two design details that would help restrict the spread of fire between the houses.
Answer
To restrict the spread of fire between semi-detached houses, the following design details are essential:
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Concrete Block Partition Wall: The wall between the two houses should be constructed using concrete blocks laid on flat. A typical dimension is 440 mm x 215 mm x 120 mm. The blocks should finish 25-30 mm below the upper edge of the rafters or trussed rafters, providing a robust barrier against fire spread.
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Insulation and Air Gaps: In the cavity between the roofing batten and the party wall, mineral fiber or wool quilt should be placed to resist heat and flames. The quilt should be positioned in mild compression with an underlay installed beneath the roofing battens, further minimizing fire transfer.
Step 2
Using notes and freehand sketches, show two design details that would facilitate escape from a domestic dwelling in the event of an outbreak of fire.
Answer
In the event of a fire, egress is crucial. The following details are recommended:
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Escape Routes: Design staircases that have no exit into kitchens, where a stair exists from the bottom living room to the exit. The maximum travel distance from any point in the living area should not exceed 4.5 m.
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Window Access for Escape: Ensure that windows, dormer windows, or skylights in habitable rooms comply with minimum clear opening dimensions of 0.33 m, and are positioned 800-1100 mm above the first floor level for safe egress.
Step 3
Outline two considerations to be observed when fitting a smoke detection system in a house.
Answer
When installing a smoke detection system, the following considerations should be observed:
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Power Supply: Smoke detectors must be powered by either battery backup or a hardwired connection to ensure functionality during power outages. All habitable rooms should have at least one unit, with interconnected alarms for enhanced safety.
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Placement and Detection Units: Detectors should be located in key areas, including hallways and living spaces, ensuring they are positioned not more than 7.5 m apart. Alarms should also be fitted in corridors to ensure they are within 300 m of any living space.