Ventilation calculation conundrum!!

Hi everybody!

Never thought I'd end up asking for assistance, but here goes!!

I have a bit of a conundrum concerning a ventilation calculation.

Have a domestic kitchen to ventilate with a ceiling-mounted unit.

Building Regs say must be a minimum of 60 l/s.

I calculated using the airchange method, and this is where it gets sticky...

The room is 39.23m3

multiply this by the ave. airchange factor (15)

which gives a flow rate of 588m3/hr.

which to achieve, you need to invest 200 quid in a suitable extract unit.

Not going to be acceptable to the customer!!!!!

What would you chaps do?

four things

did you measure the floor space then floor to ceiling to get volume?

(if so did you allow to take away space ocupied by cupboards etc?)

suggest having large cooker hood

installl reasonable sized fan anyway (i seem to remeber Gwailo, mentioning most fans are not up to spec, or something like that) I have installed a fan in the bathroom, spec says it is big enough, but we still get steam, so i ended up putting another in series with the first, much better.

have you considered these people

Hi Breezer

Yes did calc room size as you suggested, and did subtract amount for furnuture. But there is very little furniture apart from table and fitted kitchen- already accounted for.

Cooker hood is not what they want : a because it would mess up brand new (get this) £35K kitchen, and b because their main worry is the oven, which is away from hob.

Yes, they have had Vent Axia Centrif 250 recommended to them by their local wholesaler, so that is what I was focusing on.

If I fit a lesser fan , does this mean that the building inspector will not pass it?

Gwailo would be best to answer that one, but if its a 35k kithchen tell them a £200 fan is what is required, and good luck with them (i have known people who spend lots on thing to quibble over pence on another)

and besides if you put in a smaller fan and it fails, who is going to pay for the bigger one, not them?

Exactly, breezer, this is a well-known problem.

I live in a very affluent area of Stockport. Lots of my customers are very well-off, and the more money they have, the more times they say to me "If the price is right, you can have the job", or "give me a decent price and I'll see that all my friends/rellies get to hear about you."

Joe Public with a less bulgy bank account just accepts the estimate and I get on with it.

Of course, if they really want something, they'll pay for it (flash kitchen, Jag etc)

I remember when I was an apprentice, we did a job for a (very exclusive) kitchen co. The job was for a well-known jeweller (retired) in a huge house in Lytham St Annes. The kitchen cost in excess of £50K.(The house was worth £1M back in 1985). And here was the jeweller quibbling with my boss about £30 on the bill. "I didn't get where I f*****g am today by paying well over the odds you know!"

Cheeky b*****d!!

I only fell for the "reduced rate" scam once, never again.

Another recent experience was a bloke I'd done a few very small jobs for, and then he wanted a shower upgrade to 9.5kW.

Picture the scene: existing 7 kW shower installed in 1982 in 1960's semi. 4mm cable, old wylex (wooden backboard) CU with 60A switch, no rcd (i know some debate these, but I always fit them), no supp bonding, no main bonding etc....

Well, you'll need all of these points addressing,I told him and gave him the estimate.
I popped round to ask if he had considered my estimate, a few days later, and he had the work done by someone else who had told him "Oh, don't worry, you don't need all that s**t doing - he's ripping you off. I'll see you right for much less than that"

So it was that my customer had a 9.5kW shower installed with the existing 30A 3036 fuse, existing 4mm cable (20m run), same board, no bonding of any description, and a ceiling-mounted 32A plateswitch in zone 1!!

All for a snip........3/4 of my estimate total...........

Of course, he's legged it, mobile untraceable (unregistered PAYG probably threw sim in bin) no landline, no address, no receipt no nothing.

Now he has to pay all over again and more to put this s***e job right.

Unbelievable, isn't it?

It's a game innit, eh? I appreciate hearing all these stories though, it confirms my decision to try to stick to my guns. Plus my own experiences bear out what a rod you can make for your own back if you weaken and go for the low quote.

I did a job for a bloke not so long ago and allowed myself to be slightly cowed by the guy's cocky, "I could do it meself, if i could be bothered" approach. Turned out the reason he didn't want to do it was he couldn't drill through his house walls, which are made from - wait for it - solid concrete, eighteen inches of it. I bust an expensive drill bit getting through it and a job I'd expected to take an hour took almost three, which effectively wiped out any profit. I'd taken the view that any work was better than no work. The same thing applies to doing substandard work simply because it's there for the taking. I'd rather gain a reputation for fair pricing for a bl**dy good job and just walk away from the temptation to bodge it for a few quid.

Yeah, me too Dingbat. See my post in "NICEIC and Co."

Actually did a job this morning - a shower for a builder friends uncle.

He told me of the last job he went on another shower and the spark was supposedly NIC - all he did was reconnect the cable sticking out of the wall to the new shower. My mate Brian said "is that all? I could have done that. Don't you need an isolator?"

NIC sparks response - "Nah, you've got the mcb for that......"

Is that or is that not taking the p**s??

I left the building trade because I got fed up with the rich people not paying up,why are they so mean ?

masona said:

I left the building trade because I got fed up with the rich people not paying up,why are they so mean ?

Click to expand...

They are rich because they are mean. They are mean because they are rich.

hmmmm, I rather be poor than happy

securespark said:

Yeah, me too Dingbat. See my post in "NICEIC and Co."

Actually did a job this morning - a shower for a builder friends uncle.

He told me of the last job he went on another shower and the spark was supposedly NIC - all he did was reconnect the cable sticking out of the wall to the new shower. My mate Brian said "is that all? I could have done that. Don't you need an isolator?"

NIC sparks response - "Nah, you've got the mcb for that......"

Is that or is that not taking the p**s??

Click to expand...

I went to a job today to check some readings a spark took whilst carrying out a test on a rewire that a NON NICEIC spark done......

TT System, earth rod outside sticking out of the ground by about a foot, with a reading of 497 ohms........12 way split-load board, 100mA & 30mA, all circuits on the 100mA side...other 6 ways left exposed, no blanks.....Cables clipped back with conduit saddles, cable runs around windows and plastered over, not sunk in......the list went on with departures......

Now if they got a NIC firm in the first place and the work was that bad, it would of been done by another firm at no extra cost to the customer. There are cr*p sparks out there, NIC and Non NIC, but you got "some" backup.....

After seeing the above job, I was totally disgusted that someone had the audacity to call themselves a spark let alone competent......I would name the company but me thinks I would open a can worms on myself.....

Funny thing was the spark is taking them to court for not settling the outstanding bill of £200

il

i agree there are good and bad sparks, the problem is that joe public goes nic to ensure a superior quality, but sometimes end up being ripped off. And who are they to know whether the job's a good un or not?

As far as they're concerned the nic guy has done an A1 job, dotted i's and crossed t's etcetera.

Yes, they have comeback, but if they think the blokes done them proud with a top-notch job, they're not going to call on the organisation for back-up.

but if they think the blokes done them proud with a top-notch job, they're not going to call on the organisation for back-up.

Click to expand...

This regardless of NIC or not, and most of the time the sparks will do a decent job any-hoos, but the NIC is there to protect the consumer as would of with the job mentioned above.

I do believe that the electrical industry needs the NICEIC or an equivalent governing body to maintain a high standard and sparks to be assessed rather than companies. This week has been a bad one for me, I've been to loads of jobs where sparks (NIC and Not) are screwing up big time, even the sparks that work for us seem to be cutting corners.......I dunno, maybe its me bein over the top.....

No, high standards is a very good thing.

I have actually adopted one of NIC's practices, namely when I do an estimate, I check main bonding as well, esp. if the work is a shower or shower upgrade.

I've seen some odd things like cables attached to the street side of the pipework, sparks going way out of their way to bond the gas pipe next to the meter when it's outside, and even a main bonding connection to the neutral terminal.

But as discussed b4, the main problem is customer looking at estimate 1 (yours) seeing £2X, looking at estimate 2 (cornercutter) seeing £X and wondering why the bill is twice as much for (seemingly) the same work. Well, they don't know what's involved, but the end result is the same.

Why should they pay twice as much? In the commercial world, price is not the only deciding factor, but in house-bashing land it jolly well is.

I must be looking in the wrong scope.....

Our company prices are not raised by being in the NIC......granted there more than the one man bands, but that cant be helped....

We have 30 sparks each with a sign written van, half of them with test kits and guaranteed that some-one will get to you same day (even after hours) and backup if something is not right a manager / supervisor will be round and sort the problem and all that gets reflected in the extra ££s.

I think we charge about £120(ish) for a Periodic, £250(ish) to replace a board (MEM / Crabtree etc)....I dont know how that compares with the rest....