BSS ventilation

[Polishicebreaker]

Dear Boaters, I have to increase my ventilation by this much:

 

upper ventilation

18448mm2

lower ventilation

8,126mm2

 

That seems like quite a lot, my boat doesn't have mushrooms. I guess I may need to hack some In? 

Big door vents maybe?

 

any advice appreciated 

 

many thanks!

[George and Dragon]

3 mushrooms would give you about 20000 mm^2. 

An additional 6"x3" low level vent would more than suffice.

[MtB]

29 minutes ago, Polishicebreaker said:

Dear Boaters, I have to increase my ventilation by this much:

 

upper ventilation

18448mm2

lower ventilation

8,126mm2

 

That seems like quite a lot, my boat doesn't have mushrooms. I guess I may need to hack some In? 

Big door vents maybe?

 

any advice appreciated 

 

many thanks!

 

 

Why? Is this a BSS fail?

 

The do seem like large areas, I'd be inclined to do the calcs yourself and check. 

 

 

[Tracy D'arth]

28 minutes ago, Polishicebreaker said:

Dear Boaters, I have to increase my ventilation by this much:

 

upper ventilation

18448mm2

lower ventilation

8,126mm2

 

That seems like quite a lot, my boat doesn't have mushrooms. I guess I may need to hack some In? 

Big door vents maybe?

 

any advice appreciated 

 

many thanks!

For a non hire or let for rent boat ventilation is advisory only in the BSS.  Why do you have to increase it?

[MtB]

Chapter and verse in here:

 

https://www.boatsafetyscheme.org/media/299273/bss-examination-checking-procedures-core-private-boat-public-interim-complete-compress.pdf

 

Probably! 

[MtB]

4 minutes ago, Tracy D'arth said:

For a non hire or let for rent boat ventilation is advisory only in the BSS.  Why do you have to increase it?

 

 

Is the ventilation for open flue appliances also advisory-only?

 

I had a cursory look through my own link and couldn't find it.  

[Polishicebreaker]

Ah I've just seen it's marked A on the list-  this means advisory?

[Tracy D'arth]

6 minutes ago, Polishicebreaker said:

Ah I've just seen it's marked A on the list-  this means advisory?

Yes.

[Polishicebreaker]

ok great thanks!! 

 

As I haven't been gasping for breath lately, and my dodgy back doors have a pigeon sized gap at the top, I'll prob leave it!

[Steilsteven]

I've always considered low level ventilation to be nonsense and simply unachievable on a boat.

Low level, when talking about houses, means close to floor level and when combined with high level ventilation creates a through flow of air by convection.

Every four years I'm issued with a warning notice saying that 'Petra' has no low level ventilation and every four years I say that low level ventilation is impossible.

They say that I could fit a grille in the door to which I point out that the bottom of door is more than 4 feet from the floor and the vent would be so near to the roof that it, in reality' would be high level ventilation.

 

Keith

[Tracy D'arth]

If those gaps around doors are permanent  and  measurable, then they can be counted in the ventilation calculations.

[Onewheeler]

I only realised recently, and it's not been noticed in six BSS examinations, that the nice louvre vents on the front bulkhead are screwed onto solid sheet steel!

[cuthound]

2 hours ago, Tracy D'arth said:

If those gaps around doors are permanent  and  measurable, then they can be counted in the ventilation calculations.

 

I tried that when I was on our last shareboat when the BSS examiner failed it.

 

He told me it was"fortuitous ventilation and couldn't be included". 

 

I asked him how the air knew that it couldn't go through the visible gaps. 😄

 

I then played my trump card and explained that although a shareboat it was licensed as a private craft and therefore the ventilation requirements were only advisory.

 

He stormed off in a huff, returned 2 weeks later and persuaded the next co-owner that the back door needed a huge hole cutting in it. 😡 

[Ex Brummie]

2 hours ago, Tracy D'arth said:

If those gaps around doors are permanent  and  measurable, then they can be counted in the ventilation calculations.

I have two hatches that hold the lid away from the roof when closed and the examiner includes that gap in the calculations.  Certainly adventitious ventilation cannot be included in houses under building regs so I suppose such gaps wouldn't count as they're not really designed.

[MtB]

22 minutes ago, cuthound said:

He told me it was"fortuitous ventilation and couldn't be included". 

 

Actually the term is 'adventitious' ventilation and yes it is taken into account, by deducting 5kW from the heat input rating of the appliance before working out the required area of the permanent air vents. (In the GSIUR. Dunno about the BSS.)

[cuthound]

11 minutes ago, MtB said:

 

Actually the term is 'adventitious' ventilation and yes it is taken into account, by deducting 5kW from the heat input rating of the appliance before working out the required area of the permanent air vents. (In the GSIUR. Dunno about the BSS.)

 

Typical BSS examiner, can't even get the terminology right... 😅🤣