Chapter 11 Flue/Chimney systems Flashcards
A circular flue for a new gas fire requires a minimum cross-sectional area of what?
12,000 mm² this is the same as 5 inches or 125 mm
What is meant by natural draught appliance?
No fan to get products of combustion out or air in.
ACS exam question
If an appliance has a dodgy flue and products of combustion continue to enter the room is the draught diverter working?
Yes, but the flue isn’t.
Name the four points on an open flue appliance.
- Primary flue this will be covered.
- Draught diverter (Looks like a skirt).
- Secondary flue.
- Terminal.
What is the minimum length of a flue for a gas fire?
3 m straight pipe
Bends shall not exceed?
How much does a bend or a terminal reduce the height of a flue by?
There must be a minimum of how many millimetres vertical rise before the first bend?
45°
0.5 m each
600 mm
Flue twin walled will appear a dull grey colour what is between the first and second wall gap?
Air gap.
Factory insulated flue will appear very shiny or black what length can this be?
28 meters
Any opened flu appliance greater than 7 kW net will require ventilation how many cm² for every net kW above 7 kW?
5 cm²
The formula to work this out is:
Net kW -7×5 =
The appliance must incorporate a control to automatically shut down the burner if it detects no air for more than how many seconds?
Six seconds
If a chimney is 4 m high and has two 45° bends under terminal what would the height be?
2.5 m
The formula for this:
4 m - 1.5 m = 2.5 m
The bends and the terminal each equal 0.5 m .
How many metres can a single wall pipe be outside or in the loft?
0 m single wall pipe cannot be outside.
Sockets must be facing uppermost on what type of flue?
Cement based single wall flue.
Where temperatures are expected to exceed 85°? The flue pipe shall be a minimum of how many millimetres from any combustible material?
25 mm
A non-combustible sleeve may be used to provide 25 mm air gap.
BS EN 13501 - 1 : 2007 + A1:2009
Approved document B states what materials must be used in construction on external walls
Class A1
How is class 1 chimney identified?
Unlined, classic, brick chimney
Identifiable by 7 inch diameter or greater (175 mm) minimum
If a damper/restrictor is found in a chimney serving as a gas appliance, what must you do?
You must remove it or permanently fix it in an open position.
What lining is suitable for a new build?
Concrete, ceramic or clay lining
(not poured concrete)
What is the equation to measure the void volume?
W (mm) x D (mm) x height below spigot (mm) ÷ 1,000,000 = dm3
If something is found on Landlord checks as AR, what do you do with your inspection?
What must you do if you put something AR?
Carry on with the inspection in case something is found that is ID.
Once all checks are complete informed the customer of the risk, put a warning sticker on the appliance not to use, complete all paperwork.
What do you do if you find something is ID?
Stop all processes.
I bricked up builders opening is classed as what?
At risk (AR)
Pipework installed into base of unlined chimney connecting the appliance directly to the chimney base inside the base no less than how many millimetres?
250 mm
The flu should project how many millimetres in a lined and lined chimney?
Lined minimum 150 mm
Unlined minimum 250 mm
If a 5 inch steel liner was put into a class one chimney, what would this now make the chimney?
Class 2
Point to note: a 7 inch liner was installed this would still be class 1.
The class 2 chimney is identifiable by how many inches diameter?
5 inches (125 mm)
Installing a flue liner into a gas fire,, the protrusion of the liner through the plate should not exceed how many millimetres?
25 mm
Pre-cast chimney must have how many starter blocks?
3
A termination must be how many mm above the ridge of a roof if near the top and there’s not 1.5m of clearance?
600mm
Open flue terminal is not required for a flue with an axis greater than?
170mm
The openings in an open flue terminal must be sized to allow entry of ??mm ball but not a ??mm ball.
6 & 16
Suitable terminals for open flues, all the holes on the terminal added together in total should be what size compared to the flue opening?
Twice the size of the flue opening.
