ACS Question stumped me

[AnonPlumber]

Hi,

I`m about to take my ACS theory and I was running through some Mock exams and came up against this question...

Where an open flued gas appliance installed in a hallway cupboard, and having its combustion and cooling vents pathway installed via the bathroom and hallway, would be classed under what category of unsafe situation (if the appliance showed no signs of distress).

A) AR
B) ID
C) Banned Location
D) Acceptable

I answered (AR) and got it wrong. I searched the entire GSIUP for the term "Banned Location" too (the correct answer). Is this a dodgy question or just a misleading answer choice?

Also if anyone could point me to the relevant regulation please.

 

[ShaunCorbs]

ID as you can't have any vents for a open flued appliance in a bathroom

 

[stani]

I think the banned location is the bathroom, memory failing, but I think it's something like you can't have an OF appliance in a bathroom, so trying to ventilate via the bathroom brings up this banned location, someone with a better memory will be along soon

 

[AnonPlumber]

Thanks for the quick replies. I kept looking and found a passage in one of my books that states that "...the Gas Regulations restrict the use of such appliances, stating that they must not be installed in, or take their air supply from, a bathroom/shower room."

I just wish I could actually find the regulation

 

[ShaunCorbs]

Thanks for the quick replies. I kept looking and found a passage in one of my books that states that "...the Gas Regulations restrict the use of such appliances, stating that they must not be installed in, or take their air supply from, a bathroom/shower room."

I just wish I could actually find the regulation

Under ventilation

 

[Solo Heating]

This is a classic example of mis-leading the candidate by the examiner and why many people struggle. The answer could also be B since it is definitely ID but the examiner has probably never done gas work in their life so doesn't understand why B & C are both relevant. In real life, either would suffice since you'd have to act to decommission the appliance if you ever found this situation as it's ID.

For a summary of the regs, the unsafe procedures list does state what can and can't be installed in a bathroom and bedroom.

Good luck with your exam. Take it slowly and methodically and you'll be fine. It's all open book and the exam paper will tell you which document to refer to for each question.

 

[townfanjon]

Absolutely stupid bloody question

 

[ShaunCorbs]

The way I read it

It's already installed so ID

If someone asks you to install it in there sorry customer it's in a banned location

 

[JVTrades]

Absolutely stupid bloody question

When I did my last assessment I was horified to see that although the gas world has moved on, the assessment hasn't. So much stuff that just isn't relevant to the majority of work you'll be doing out there. Medium pressure gas meters - haven't seen one on site yet in the last 10 years!

 

[JVTrades]

Any other gas engineers out there agree with me that the 5 year assessment is not fit for purpose.

 

[townfanjon]

The way I read it

It's already installed so ID

If someone asks you to install it in there sorry customer it's in a banned location

Exactly !!!!!

 

[AnonPlumber]

Thanks guys/lasses, its nice to know now that this kind of question might occur. I'd say it wasn't fair but something tells me that wont wash during the exam.

 

[Solo Heating]

You'll get plenty of questions like this. Watch out for ones where they use double negatives so it sounds like a situation is wrong when actually it's right and vice versa. The exam becomes more like an english paper.

Having done my ACS 4 times now over 15 years I can say that very little has changed and I'm not sure it is fit for purpose. The industry has changed quite a bit in that 15 years and manufacturer's requirements often differ from the ACS viewpoint.

 

[AnonPlumber]

Watch out for ones where they use double negatives so it sounds like a situation is wrong when actually it's right and vice versa.

Yeah I hear you. However I just found this one... If you convert the values to either m3/hr or ft3/hr you can answer either C/D. They were looking for the answer in ft3 apparently. The Answer should have been, 94.7 ft3, 2.65 m3 by my math.

 

[ShaunCorbs]

Yeah I hear you. However I just found this one... If you convert the values to either m3/hr or ft3/hr you can answer either C/D. They were looking for the answer in ft3 apparently. The Answer should have been, 94.7 ft3, 2.65 m3 by my math.

View attachment 29578

It's an imperial meter I wouldn't convert it to metric just work it out imperial

Just to confuse you even more it's slightly out

94.0ft3 and boiler is around the 29kw rating

 

[AnonPlumber]

It's an imperial meter I wouldn't convert it to metric just work it out imperial

Just to confuse you even more it's slightly out

94.0ft3 and boiler is around the 29kw rating

oh great lol

 

[firemant]

I am going to stick my neck out. It is "banned location", because there is (sort of) now no NCS, as part of the procedures.

If the ventilation is greater than 90% of the required, then just because the ventilation path is via a bathroom does not inherently make it ID. There would have to be a fault on the boiler/flue causing spillage for there to be any ID. The only increase in danger would be if the POCs were seeking an exit. In practice, in the event of spillage, and POCs entering the bathroom, the bathroom vent would probably help by diluting the POCS.

TBH, if I was choosing between "NCS" and AR, I would have to stop and think. But it is not ID. I am due to retake next March, so I will have to make sure I am up to speed on this one - I have never seen "banned location" as a "category" of unsafe situations.

 

[AnonPlumber]

Some more examples of Questions that dont make any sense... Its only these stupid ones I`m getting wrong but I think these are more mistakes than deliberate obfuscation.

 

[ShaunCorbs]

They seem pritty straight forward

Are you doing a gas short course (6weeks gas safe) ??

 

[AnonPlumber]

They seem pritty straight forward

Are you doing a gas short course (6weeks gas safe) ??

The correct answers are the blue arrows... but by my books are wrong.

I`ve done the course I have my ACS theory in just over a week

 

[ShaunCorbs]

The correct answers are the blue arrows... but by my books are wrong.

I`ve done the course I have my ACS theory in just over a week

With q 30 I think your getting confused with insulated twin wall flue pipe

In your books there should be a maximum length for single wall flue pipe, also should say about condensation either just before or after

 

[AnonPlumber]

I Don't mean to come off impolite I just edited this for brevity.

Q28... I'm looking in my Site Guide, the answer is clearly 1500mm not 600mm. Not once is 600mm a minimum horizontal dimension regarding OF terminals. Therefore I was correct and the online test was wrong?

Q30... "A" and "C" are both true.

I can find no reference to insulating single wall flues in roof spaces only that its not good to install single wall flue in roof spaces to begin with (regarding roof voids as external environments). Therefore I was correct again?

 

[ShaunCorbs]

23 have a read of this

http://www.pearsonschoolsandfecolle...-in-Plumbing-Studies/Samples/Level3GAS_SB.pdf

30 what statement is not true b and c are true so it only got a left which is not true

 

[AnonPlumber]

23 have a read of this

http://www.pearsonschoolsandfecolle...-in-Plumbing-Studies/Samples/Level3GAS_SB.pdf

30 what statement is not true b and c are true so it only got a left which is not true

Although that document has a lot more information in it and is better organised than the On Site Guide I have been working from the information regarding the horizontal minimum is the same.

Are you saying that it is not 1500mm and should be 600mm?

Also in that document are the exact same tables and diagrams of dimensions regarding Open Flue Terminal placement and minimum clearances that are in the "On Site Guide" I referred to earlier.

Am I incorrect in saying that you don't insulate a single walled flue in an external environment? By the document you linked installing a single walled flue is an absolute no no in external environments so B) is even more wrong.

I'm not gas safe yet but there is definitely something wrong here. Either "I don't get it" in which case I`m in serious trouble or something else is wrong in which case I`m in trouble anyway

 

[ShaunCorbs]

Although that document has a lot more information in it and is better organised than the On Site Guide I have been working from the information regarding the horizontal minimum is the same.

Are you saying that it is not 1500mm and should be 600mm?

Also in that document are the exact same tables and diagrams of dimensions regarding Open Flue Terminal placement and minimum clearances that are in the "On Site Guide" I referred to earlier.

Am I incorrect in saying that you don't insulate a single walled flue in an external environment? By the document you linked installing a single walled flue is an absolute no no in external environments so B) is even more wrong.

I'm not gas safe yet but there is definitely something wrong here. Either "I don't get it" in which case I`m in serious trouble or something else is wrong in which case I`m in trouble anyway

Depends on roof angle as it doesn't say, just says steep I would go for more than 45D measurement,

You can't have single wall flue externally, in a loft isn't external

and depending on length and dia it may need to be insulated

Tbh it sounds like you need a few more lessons

 

[Jehannum]

Yeah I hear you. However I just found this one... If you convert the values to either m3/hr or ft3/hr you can answer either C/D. They were looking for the answer in ft3 apparently. The Answer should have been, 94.7 ft3, 2.65 m3 by my math.

View attachment 29578

The fact that they're using units of volume for flow rate (missing the "per hour" bit) would make me mistrust this exam as a whole. It might be OK for practice but I wouldn't fret too much over individual questions.

As for the bathroom question, Technical Bulletin 001, situation 7.5 states that a flueless or non-room-sealed appliance in room containing a bath or shower is ID.

Excessive water vapour in air adversely affects combustion. This is why Regulations prohibit non-room sealed appliances in bath or shower rooms. If an appliance takes its combustion air from a bathroom then obviously the same problem is going to manifest. ID is a perfectly reasonable answer.

The open flue / roof question is complete nonsense and it's very badly worded. The correct answer should be 1500 mm.

 

[Chuck]

Yeah I hear you. However I just found this one... If you convert the values to either m3/hr or ft3/hr you can answer either C/D. They were looking for the answer in ft3 apparently. The Answer should have been, 94.7 ft3, 2.65 m3 by my math.

View attachment 29578

(1 ft^3 / rev) * (1 rev / 38 s) * (3600 s / hr) = 94.74 ft^3 / hr

1 m^3 = 35.32 ft^3
=> 1 = (35.32 ft^3 / 1 m^3)
=> 1 = (1 m^3 / 35.32 ft^3)

Hence (94.74 ft^3 / hr) * (1m^3 / 35.32 ft^3) = 2.682 m^3 / hr

So D seems to be the answer expected.

There is a technical issue with the question. This is that ft^3 is a 'volume' not a 'rate'.

 

[ShaunCorbs]

(1 ft^3 / rev) * (1 rev / 38 s) * (3600 s / hr) = 94.74 ft^3 / hr

1 m^3 = 35.32 ft^3
=> 1 = (35.32 ft^3 / 1 m^3)
=> 1 = (1 m^3 / 35.32 ft^3)

Hence (94.74 ft^3 / hr) * (1m^3 / 35.32 ft^3) = 2.682 m^3 / hr

So D seems to be the answer expected.

There is a technical issue with the question. This is that ft^3 is a 'volume' not a 'rate'.

Agree with the calcs but we gas rate appliances, it's been classified as that for years

Gas Rate = the amount of gas used in an hour / range rated

 

[Chuck]

Agree with the calcs but we gas rate appliances, it's been classified as that for years

Gas Rate = the amount of gas used in an hour / range rated

Interesting. I'm not an installer and am not familiar with that convention.

I've only come across 'gas rate' as an abreviation for 'gas volumetric flow rate' with volume/time units, e.g. on the HHIC benchmark checklist via WB:

"Gas rate [ ] m^3/hr or [ ] ft^3/hr"

or as a power, e.g. in kW, e.g. the 1989 Gas Cooker Regs

"in the case of an appliance fitted with a burner the ignition of which can take place in a closed compartment with the door closed, the gas rate to any such burner which is not controlled by a flame supervision device does not exceed 600 watts;"

 

[Jehannum]

Any 'rate' necessarily includes a time component; otherwise it's not really a rate but an 'amount'.

Every appliance manufacturer's instructions I've seen uses "ft3 / h" or "m3 / h" as the unit of gas rate. This makes sense because the time component (hour) is included in the information. If it were not, you'd have to know the convention that it meant gas consumption in an hour. It wouldn't be self-contained information. It would also be dimensionally incorrect, i.e. the units would not work out properly if you used it as part of a formula.