Diversity Factor Calculation

[richard978]

Could someone work out total KW input for the following applying the diversity factor.

36 KW combi
24 KW combi
Cooker 12.9kw


It would appear according to gas Safe that my original assessment was wrong that they had exceeded badge capacity of a U6 as I didn't apply diversity factor.

Now the original plumber recorded 10mb working pressure with both boilers working on hw. My take is that you use the highest rated appliance not both. I also noted that all three appliances exceeded badge capacity. Now after working out diversity it comes in at 55.74kw.....is my calculation correct

 

[ShaunCorbs]

Around 73kw

I wouldn’t allow diversity on the two Combi Boilers as there’s a good chance they could be both running on hw at the same time

I would allow diversity on the cooker tho

 

[richard978]

Around 73kw

I wouldn’t allow diversity on the two Combi Boilers as there’s a good chance they could be both running on hw at the same time

I would allow diversity on the cooker tho

I work for a gas transporter and I find it incredible that people are pushing the capacity of domestic meters .... especially when it's not just the meter that should be considered....it's the service and distance from the main as well.

It's the first time I've heard of diversity factor If I'm honest and while it sort of makes sense I can honestly see both boilers being used simultaneously and then affects the safety of the cooker.

 

[SJB060685]

Can I ask, if allowed, what is this diversity factor with regards to gas? I've only worked on oil appliances but do like to further my understanding of other energy sources.

 

[richard978]

Can I ask, if allowed, what is this diversity factor with regards to gas? I've only worked on oil appliances but do like to further my understanding of other energy sources.

As far as I can tell it's 0.8 for a boiler and 0.6 for a cooker. I'm not clear on whether you would include the combi or not as the post says they could easily be used at the same time. I should imagine it was designed for a boiler a cooker and say two gas fires.

 

[ShaunCorbs]

It’s a factor/ calculation on the total load of an appliance vs how often it runs at max capacity

 

[SJB060685]

Thank you guys, much appreciated

 

[richard978]

It’s a factor/ calculation on the total load of an appliance vs how often it runs at max capacity

So do you use judgement on when to apply it or do you blanket apply the diversity factor to all the appliances.

For example two combi boilers one in a house and the other in a granny flat might be run at the same time ...total requirement of 60kw but if apply a diversity of 0 8 I get just 48kw.


It makes very little sense and a complete mockery of gas Safe rules

 

[ShaunCorbs]

I would do Combi Boilers no

Normal heat only boilers yes

Cookers and fires yes

 

[richard978]

I've had a look and the factor for a heat only is 1 and a combi is 0.8.

Now with both being combination it gets a bit confusing.

Obviously the meter is one issue but the service will be no more than 25mm. So even if the meter will cope the service certainly won't. Which will mean a upgrade survey.

Do you engineers consider the gas service when installing or would you just expect the transporter to upgrade if the service can't deliver 6m/hr.

When I was fitting 40kw was the max I would ever fit and that was rare. Water flow rates alone would often mean big combis would be a waste ful