Thermal Insulation Flashcards
Where is insulation used?
As a component of walls, ceilings and floors.
What two things does insulation result in?
1/ reduces energy consumption
2/ maintains interior surfaces at comfortable temperatures.
Do insulation materials need protection? Give an example of an insulation product and a response to it.
Because insulation properties are low density, they are fragile and easily damaged.
Foam plastic insulation is combustible and hence requires fire protection. Foam plastics also degrade rapidly when hit by light.
For these reasons, insulation materials are details as being sandwiched in middle of an assembly, between the interior and exterior finishes.
What is a major concern when choosing between insulations?
Insulation materials vary substantially in efficiency. A deciding factor is surprisingly, ‘will the insulation actually fit into the assembly?’
Why and when is glass fibre batts insulation used?
Glass fibre insulation is the most value-for-money insulator available.
Glass fibre can only be used in dry conditions because glass fibre loses its insulation value when wet.
Glass fibres batts cannot be compressed because its insulating power comes from being thick and springy.
What are wet areas of a building that might require insulating and what insulation is used for this purpose?
1/ outside a foundation wall
2/ inside a masonry cavity
3/ inside a protected membrane roof
Closed cell polystyrene foam is used for this purpose because it retains its insulation value even when wet for long periods of time.
In cold climates, what modification is added to the insulation?
A vapour barrier is placed, in front of the insulation on the warm interior side.
What is a thermal break?
What materials are thermal breaks used for?
A strip of insulating material inserted into a building assembly to prevent rapid heat conduction through dense, high conductive materials such as masonry and metals.
What eight types of thermal breaks does Edward Allen explain?
1/ thermal resistance of steel stud wall.
2/ thermal break in aluminium window frame.
3/ thermal break in aluminium cladding system.
4/ foam plastic insulation against wood studs.
5/ thermally broken wood stud walls.
6/ concrete masonry unit with minimal webs.
7/ inside furring and insulation of concrete masonry wall.
8/ exterior insulation and finish systems (EIFS) on concrete masonry wall.
1/ thermal resistance of a steel stud wall.
Describe the problem, the solution and the result of the solution.
Draw along.
1/ The spaces in between steel studs can be effectively insulated with glass-fibre batts, but the studs themselves act as thermal bridges and as a result will rapidly conduct heat though the wall.
2/ The thermal bridge is partially broken by the thermal break, a strip of insulating plastic foam placed in between the exterior cladding and the steel studs.
3/ Though the thermal break cannot reach the same level of thermal resistance as the glass-fibre batt insulated airspace, it raises the temperature of the steel studs well above the local dew point so that no condensation forms within the assembly, damaging the insulation and corroding the steel studs.
2/ de-bridging aluminium frames.
Describe the principle, the problem, the solution and the result of the solution.
Draw along.
1/ aluminium conducts heat more readily than steel.
2/ In cold climates, aluminium window and door frames, aluminium cladding systems pass all the way from the inside to the outside. Frost and water can deposit on the outside surfaces of these assemblies and cause damage.
3/ to prevent this thermal bridge, there are many different solutions. One is to cast hard plastic into a groove in the aluminium assembly. To ‘de-bridge’ the aluminium member, the bottom of the hard plastic filled groove is milled out, leaving a thermal break between the aluminium areas reaching the inside and outside.
3/ thermal breaks in aluminium cladding systems
Describe the principle, the problem, and the two types of solutions.
Draw along.
1/ aluminium conducts heat more readily than steel.
2/ In cold climates, aluminium window and door frames, aluminium cladding systems pass all the way from the inside to the outside. Frost and water can deposit on the outside surfaces of these assemblies and cause damage.
3/ A second type of thermal break is a simple plastic or rubber strip inserted in between the inner and outer parts of the mullion during assembly.
4/ a third type of thermal break are small, intermittent plastic clips which mount the cover components of the mullion.
4/ foam plastic insulation across wood studs
Describe the principle/problem and the solution.
1/ though wood is less conductive than masonry or metal, wood studs still conduct much more heat than the glass fibre batts in the insulated segments of the wall.
2/ plastic foam can be added across the outside or inside of the framing members for a thermal break. It can be continuous layer or individual strips, attached to each stud.
5/ thermally broken wood stud walls
Describe two other solutions.
1/ apply horizontal furring strips and apply another layer of insulating batts across the inside or outside face of the studs.
2/ construct another stud wall just outside the first, leaving an inch of airspace between the studs to act as a thermal break.
6/ concrete masonry unit with minimal webs
Describe the current insulation methods, and the underlying flaw. How has this been minimised?
1/ although hollow concrete masonry units can have their cores filled with granular fill insulation or plastic foam inserts, the webs themselves are bridges.
2/ There are now hollow concrete masonry units with small enough webs whereby the thermal bridging is negligible.
