Tutor Lesson with students on Ventilation

Tutor lesson with students on ventilation

by Ice one

​Ventilation

• ​In this lesson we are going to do a quick recap to make sure you guys understand ventilation.

• ​Not only ventilation but where appliances can and can not be installed.

• ​As gasfitters we have a responsibility to make sure the public / customers are safe.

​Flueless gas heater

• ​Here we are going to find out if the room is big enough for this heater to the right.

• ​The room size we have is 5x5x2.4= 60 meters cubed.

• ​The mj rating of the gas heater is 15 mj/hr.

• ​The heater is a thermostatically controlled heater.

• ​Is the room big enough?

​Flueless gas heater

• ​So first of all we need to find out what the MJ allowance for the appliance is.

• ​Attached to the right is a extract form the codes of practice.

• ​What allowance are we allowed for our heater?

• ​Once we have found that out we can use our ventilation triangle to figure out if the room is big enough as follows.

​Room size calculation.

• ​So if we look at the triangle to the right we can use it to see if the room is big enough.

• ​To find out the information you want you cover the section of info you want and do the calculation that is left.

• ​For example I want to know if the heater can go in that room.

Discuss answers​

​

​Ventilation calculation part two

• ​Now we have another example.

• ​WE have a gas hot water cylinder in a cupboard, the cupboard size is 1x1x2= 2m cubed

• ​The MJ rating of the hot water cylinder is 56 MJ/HR.

• ​Is the cupboard big enough?

​Hot water cylinder

• ​Now we have figured out our allowance, what is the allowance for a gas hot water cylinder?

• ​If you look at the document to the right what the MJ/h per cubic meter? (this is in your blue book) and the code if you cant read it.

Discuss answers​

​

​Example for H/W/C

• ​So we wanted to know if the cylinder could be installed in that cupboard.

• ​So what we did was cover the bottom right of the triangle and did the calc left which was.

• ​MJ in put 56/room size which was 2m cubed.

• ​= 56/2= 28mj per cubic meter.

​Example answer

• ​So we got 28 mj per cubic meter, if we look at the extract to the right we are allowed 3MJ per cubic meter.

• ​We are well over that so now we need to add ventilation.

• ​For that we use the calculation A=FxT.

• ​On the next slide we will go over this.

​Vent size

• ​Now we need ventilation we need to use A= FxT.

• ​this means the A (area of the vent size) is worked out by,

• ​F (factor from the table in the codes) times by the T ( MJ rating of the appliance/appliances in the room.

​Vent size

• ​For example we are going to say we can get ventilation from outside,

• ​So our calculation is 300x56= 16,800 mm squared. (remember if you square route this calc you will get your cut out size ie 129mm hole)

• ​Now the question is how many?

• ​And where to put them?

Discuss answers​

​

​More Examples

• ​Flueless gas heater in a bedroom 15mj/hr and room size is 38.4 m cubed.

• ​Does it need ventilation?

​More examples

• ​A opened flued fire place with a MJ rating of 78 mj/hr in a 18 m cubed room.

• ​Does it need ventilation?

​More examples

• ​For the fire place we cant get ventilation from outside we can only get it from the bedroom next door.

• what size vents are needed?

• And how many and locations?

• ​If it was a flueless heater where would the vents need to be then?

​More examples

​A gas hot water cylinder with a mj/hr rating of 56, in a 2x2x1.8 cupboard?

​

​Does it need ventilation?

Discuss answers​

​