Ex Gas Safe Inspector Explains The New Tightness Test Rules w/ Terry Sawyer

One of the biggest changes that people still seem to be not really able to get their head around is you now, if you find a leak, you now have to isolate the appliances. So for whatever reason, there is no way you can isolate an appliance, then you have to go with worst case scenario, which is basically the largest installation volume that we're allowed to go to. And that's going to catch people out. Basically, you've got till the 30th of September to to switch over and learn the new way. After that, if you don't know it and you have a GasSafe inspection, then you will be defected on the fact that you don't know it.

In a sentence or two, why should people care about this conversation?

Why? Because it's probably the biggest change that's come to the industry for most gas engineers for quite a while. And obviously the old way of doing the tolerant-judge inspection has been in for so long now, it had minor adjustments but nothing really as big as this, which has completely changed the way obviously we deal with gas leaks.

This is the Gas Engineer Podcast. I'm your host, Tullik Priest, and today I'm joined by Terry Sawyer, former GasSafe inspector and somebody who's been on social media recently breaking down a major change that's about to affect every gas engineer in the country. Welcome to the show, Terry.

Thank you.

The iGen UP1B document has just been updated to its 4th edition, and the way that you test for gas leaks is about to change. The old 4 and 8 millibar method is going, and the installation volume calculations are coming in. Terry's been digging into what this means, and he's here to walk us through it. As always, if you enjoy these conversations, then please subscribe and follow us on whatever podcast platform you're tuned in to support the podcast. Could you just give us like a brief summary to your background, just so people who haven't seen you before?

Background? I've been a gas engineer for many, many years now. A few years ago, GasSafe were recruiting for inspectors, so I decided to apply and was fortunate enough to get through the interviews and everything and become a gas inspector for part of East London and Essex. So yeah, got to be on both sides of the fence, and then yeah, decided to step back onto the tools to try and yeah, carry on doing what I'm good at, what I like to think I'm good at.

Could you kind of walk us through what the changes mean?

So the actual tightness testing procedure itself is not really changing. The actual tightness test procedure is still the same until you get to the point where you find a leak. And when we say a leak, we are talking about a perceptible movement. So basically, if you're using a water gauge, a lot of people use water gauges, then, then anything above 0.25 millibar, anything below that you wouldn't, you wouldn't be calling that a perceptible drop, basically. So you wouldn't have to worry. And if you're using a digital gauge that works to a decimal point, then you're allowed basically 0.20 millibar. Up to that is, is not perceptible drop. So below that, you haven't got to worry, right? You've got no leak. Above that is where the changes now are beginning. As you said, it's no longer going to be based on the meter size or what meter they've got. It's going to be based on the installation volume of that particular property. So this is where it's changing quite a bit. And so far, putting the feelers out, putting the information that I know out, so far that a lot of the questions that I'm getting are, how do we know the size of the gas pipe? How do we know how many elbows? How do we know anything about the installation if we can't see it? If the gas— if the gas pipe off the gas meter disappears straight into the wall or the floor, and then you see it again at the other end of the house coming out below the boiler, you know, how do we know what, what's in there? And that is probably the biggest thing that's concerning most engineers, I would have thought, by the feedback that is— that I've been reading on other, other social media posts. And I know there's quite a few guys doing— other, other engineers doing these sorts of videos trying to explain the changes and what to look out for and things like that. And then obviously the biggest feedback I'm seeing is, well, how do we know? How do we know how big the system is? You know, the gas pipe. How do we know what the insulation volume is? How do we calculate if we can't see it?

Has there been an answer, you know, on the best way to approach this?

What I've been telling people is you have to, you have to go with a) what you can see. So if you do see 22mm pipe going into the floor, into the wall, and you do see 22mm pipe coming out the other end, then you can likely assume you've got to go with the best assumption that it's going to be 22mm the whole run. And you can sort of work it out roughly meterage. And do it by that way. Obviously you're not going to get that right every time. You've got to go with what you can see. And if you have any doubt then, and you have got a leak, then you'll have to revert back to— obviously I'll come on to the chart in a little while that Gas Safe have given us to refer to with the new permissible drops. But obviously it's based on installation volume. So if that's the case that you cannot work it out, in my opinion, you're going to have to go to the largest installation volume that we're allowed to work on as domestic engineers. And work off of that. Because if you can't be certain, well, you're going to have to go worst case scenario, in my opinion.

How sensitive is it? Like, if you get the volume slightly off, does it have a big impact or is it an approximation? It's normally okay.

Not approximation should be okay. It's not going to be, you know, no one's going to be perfect with their installation volume calculations. If you can't see it, you're not going to be perfect. But the ranges in the new chart, the permissible limits chart, that tells us what we can accept as a loss, as a drop in the tolerance test, what we can accept, the ranges are quite large. So you should be able to get it within one of them. And if any doubt, you just step to the next one up and work off of that permissible drop in So that is what I will be doing because there isn't really an answer to— there isn't a straightforward answer. GasSafe aren't going to have a straightforward answer because if you can't see it, you've got to go with worst case, in my opinion.

What was the reason for these changes?

So this has been spoken about for many years and discussions I've had with ex-colleagues and stuff, just when it was being spoken about and being brought up. So from what I can see, the reason this has come about is because actually it makes sense to work out how much gas is being lost if you've got a leak. Now, if you've got a tiny gas run, you know, gas meter is below the boiler and there's a bit of 22 and a bit of 15 over, you know, a meter, 2 meters max. Well, that's going to hold very, very little gas in terms of installation volume. Now, if you've got a 1 millibar leak there, a 1 millibar leak over the 2-minute test compared to, let's say, a 20-meter run of 22mm pipe if that's got a 1 millibar leak over 2 minutes. Well, the bigger the installation volume, the more gas is going to leak out over that for that 1 millibar to drop. So this is where this change sort of makes sense, that it should have been this way in the first place. It's almost like they were just simplifying it before because actually you do want to know how much gas is leaking out. You know, you're trying to make an appliance safe, make a property safe, supply pipework safe. You need to know how much gas is coming out for it to be deemed safe or not. And this is why they've brought it in for that reason.

So it's just a much better approximation of the actual volume of gas that's actually escaped.

Yeah, because you're talking, like I say, a 1 millibar drop on a small supply and a 1 millibar drop on a large system. Well, that's a considerably bigger amount of gas on the, on the longer, you know, on the, on the bigger installation volume. And that's where the safety side of things comes in.

Hi, Producer Alex here, wondering if you knew that you aren't subscribed to the channel. More specifically, 93% of you are not subscribed, and we really appreciate you tuning in right now, but you're missing out on even more interesting content. You're already this far into the episode, so why not subscribe to the Gas Engineers Software YouTube channel? Because showing your support genuinely makes a difference. It's free, takes a second to click, and helps us continue to make the content that you want to listen to. Speaking of, let's get back to it.

One of the biggest changes that people still seem to be not really able to get their head around is you now— if you find a leak, you now have to isolate the appliances. We, we must isolate the appliances as part of this new procedure to be able to test whether the leak is pipework or the appliance. Obviously, as exactly with the old tightness test procedure, we can't any drop on pipework only. So that's why we will now isolate the appliances, something that before you didn't have to do, but now you do. Now, if you cannot isolate an appliance for whatever reason, then you have to go with worst case scenario that now you are testing as if it was pipework only, even with the appliances attached. So if there's no way of fitting a way to an isolation, a way to isolate the appliance, then you have to do a retest And we're retesting for a client for pipework only, which we know now is the same. It's zero, you know, no drop whatsoever. So that's where these sort of, this change is going to maybe cause some issues because it could be the appliance leaking. But if you can't isolate it, then that would be my next port of call would be to try and work out how you can isolate it. And if you can't, well then it's, yeah, unfortunately it's no drop at all on pipework or yeah, existing if it's pipework or new pipework as well, which is, which has not changed. That's the same.

This might be a silly question, but how could the appliance be in a permissible drop?

Right, so, so nothing's, nothing's changed in terms of pipework only. The pipework, if it's new pipework or you've just put it in, or you've got no appliances attached, even with the old tightness testing, you still wasn't allowed any drop on pipework only. That's always been the rule, no drop on pipework only. But you was never— you wouldn't necessarily isolate the appliances before. Unless a customer said, oh, I've got a leak, can you find it for me? That's when then you say, okay, not a problem. But if it turns out to be the pipework leaking, then I've got to cap your gas off. Right. So that's often when the customer would say, you know what, don't worry about it because they don't, just in case. Right. So that's a big change for me. That's one of the biggest changes is now you don't have a choice. If you've got a leak, you're going to be isolating the appliances. And if you isolate the appliances and it is the pipework, Well, now you've got to, you've got to make it safe. And that is potentially where the biggest issues are going to come from, because you could have a gas, you could have a gas run from a meter outside the house and it might run to the very back of the house and you don't see a single bit of pipe. Well, somehow you've got to get a new one in or you've got to find a leak. Yeah, it's in some, some instances it's going to be very, very difficult. And that's the difference now is you have to isolate the appliance if you do have a leak. So my one bit of advice for anyone is if you have got a leak, right? So if you have got a leak, then I would be going straight to the appliances before I do any calculations because that's going to save time doing the calculations. If it turns out to be pipework that's leaking, well, you're not allowed that. So why are you then going to go and do your calculations to find out if it's within the permissible drop or not, your limits? Because it doesn't matter. Doesn't matter if it's within the permissible, it's in the pipework. So you're not allowed anything, it's zero. So for the way I will be doing it, if I do find a leak, I will be going straight to the appliances. If it does turn out to be the appliances that's leaking, brilliant. Then I'll do my calculations and I'll find out if I'm within them limits or not. And that's probably the only amendment I would make and I will make to the way I do it. I don't see the point in doing calculations and working out installation volume if it's pipework because you've got to turn it off. You're going to have to make it safe or cap it off anyway.

Yeah. Okay. Yeah. No, that makes sense. Okay. And this of course could create issues with landlords or letting agents.

Yeah, I think so, because some of these properties have had very small leaks, you know, but they've always passed. There's never been a smell of gas for many years. We do something where we make a note of a leak. If it's 1 millibar, 1.5, 2 millibars max, anything above that, we tend to make them aware straight away. But we'll normally make a note on the certificate to say you know, tightness test leak of 1 millibar over 2 minutes, no smell of gas, and that's it. It's just a note for us. So then the following year, if we go back and it's the same, well, we just make the same note. That will highlight if the leak's getting worse or if it's staying the same. Now, that leak now has now got to be dealt with differently, unfortunately. So now that leak might turn out to be pipework. And obviously, so now you're going to get landlords and clients and customers saying, well, it's passed every other year. And you're going to get that sort of argument. So I'm trying to make landlords aware of this as well, because it's just so that they— not that they should expect it, but if they suddenly get told, no, it's done differently now, well, it could come as obviously quite a shock if there is an issue.

And it is just going to be challenging with some properties. You know, if the kitchen's at the back, it's an older property and you can't access the pipe.

Yeah, I think also trap pipe as well, which is widely used now, especially in flats and properties like that. Trap pipe runs from a gas meter, bank of gas meters normally in a gas meter cupboard somewhere, and then the trap pipe runs from there all the way to the property. So that could be a very long run. And that, if it's a very long run and it's, you know, it's quite, and it's a 35mm trap pipe, then that's going to be in the highest category and therefore you're allowed 1 millibar drop. Well, How are you gonna run a new, if you can't find the leak either at the start of the trap pipe or the end of the trap pipe and it's not the appliances, well how are you gonna find it if it's buried? You're not. And how are you gonna run a new one? Well you're probably not. So then sort of, you know, that's where it potentially is gonna cause big, you know, big issues. I mean it's rare for it to leak mid-pipe but you don't know, you don't know if it's been damaged during installation or anything like that. So it's that, that's yeah, that's where. Some issues may come from. And it might mean that when these pipes are being installed, that they are sort of tested more than once before they're buried, basically, just to be safe.

You've been in the industry for over 15 years now, never had to calculate installation volume, I'm guessing. It's not a regular thing for you, is it?

Installation volume. So installation volume was primarily for purging. So purging of the gas supply. So when you've done a new gas run, things like that, you'd be expected to purge. Now the installation volume was so that you could calculate how much gas was going to pass through the meter before all the air was out the system. So like the direct purging method. So you, so that's how you could calculate that you've purged it correctly. So installation volume is something that you learn when you are doing your, your ACS exams and when you're doing your training. Installation volume is something that you learn. Pipe sizing, installation volume, how to calculate it. So everyone has had to do this. So it's not something new, it's just something that Yeah, not many people will do, you know, not many people are going to have probably done insulation volume calculations for a very long time, in my opinion. You know, that's to me what will catch people out is they haven't done it for a long time. A lot of people are going to be going back to their books and working it out, you know, using the old-fashioned paper and pen. But yeah, people, we should all have done it. All gas engineers should have done it and worked it out and know how to do it. But I can't imagine many have for a while.

That's to be fair. If, if it's not something you do every day, um, you know, you, you will need to brush up on it.

Yeah, definitely. This IGM UP1B Edition 4 change has come into effect already, but it's not, it's, there's basically a transition period between the old way of doing tightness testing and the new way. So basically you've got till the 30th of September to switch over and learn the new way. After that, if you don't know it and you have a Gas Safe inspection, then you will be defected on the fact that you don't know it. So you've got until the end of September. So as of the 1st of October, you'll be expected to use the new way, new procedure for tightness testing.

And would using an app be acceptable? You don't have to know the writing it out on paper, manual calculations.

No different. In my opinion, it's no different to gas rating. Gas rating. I remember many, many years ago before I worked for Gas Safe, having an inspection and they asked me how do I do my gas rate? And I said, I use an app. And they was like, yeah, more than happy. So as long as I can refer to my book and be able to work out the gas rate on pen and paper, if I, for any reason, I don't have my app, my phone dies or whatever, then as long as I can still do that. So having these apps don't mean you forget how to do it on pen and paper. The pen and paper should be your bread and butter stuff, but the apps just make life a little bit easier, a little bit quicker, and less likely to make mistake if you're using an app.

Yeah, it does it the same way each time.

Yeah.

When these kind of changes come in, does it take quite a long time to kind of, um, for, for all everyone to kind of work out what the changes are, or, or are they kind of quite well advertised?

If I'm honest, they're not as well advertised as what you would expect in terms of these sort of podcasts, these chats that we're having. And a few other people have done the social media videos. They are what seem to be highlighting these changes. And you've got a couple of people who are saying, well, I've just come out my ACS renewal, you know, only done it a week ago and they didn't even mention this. So that comes down to training providers have been made aware of this, so they should be implementing this. They should have been implementing it from before it even switched over. They should have been talking about it, making sure people are aware it was coming in. I know some did, some didn't. If you don't go back for your ACS renewal, the only way you're going to know really about this update is by social media and recordings like this. I mean, don't get me wrong, if you are signed up, you know, if you're a Gas Safe registered engineer, you do get sort of emails and correspondence sent from Gas Safe to your email, sent out in the post. They do mention it because obviously it's a massive change. So the most recent correspondence come out has mentioned it. So it's more to do with reading up on it.

Okay. So it's just a, you know, you need that discipline just to kind of keep tabs of these kind of changes.

Yeah. I mean this, so the industry standard, I printed this off because I think this is going to come in very, very handy. So the industry standard update 133, It came out when the update to the IGM UP1B came out. So they brought this Industry Standard Update 133 out. Due to confusion somewhere along the line, there was a confusion with the wording, with how people were interpreting these, these new, this new procedure. They then scrapped that and they then released the Edition 2. So the Industry Standard Update 133 Edition 2, which just tries to iron out any confusing parts that was in the first update. Um, so you can get this online. This is a free download, and it basically is a step-by-step guide of exactly what you need to do to comply with this new update. And I've been telling people already on social media, print yourself off a copy, keep it in, keep it in your, in your tool bag, because you can't really go wrong if you've got it all written down in front of you. And it gives you all the information you need, even a step-by-step guide on how to do a tightness test and with the new changes. So you can't really get it wrong if you've got that bit of paper right next to you. So I've been saying to anyone watching this who hasn't downloaded it, you can get it online. It's quite easy, PDF, download it, print it out, put it in your bag. And it's even got the chart which gives you the permissible drops on there. So once you've done your calculations, you can see exactly how much you are allowed to lose in pressure over the 2 minutes based on your installation volume, and so you can't really go wrong.

Are you fed up with drowning in a pile of paperwork that comes with running your heating and plumbing business? Gas Engineer Software is an easy-to-use, all-in-one job management system made especially for UK heating and plumbing companies. From handling customer details to building quotes, issuing certificates, and sending invoices, Gas Engineer Software will help you save time, eliminate paperwork, and make running your business easy. Start a free trial by clicking in the link in the bio. Okay, and does this, um, change, add much time to doing the tests?

Um, if you find a leak, if you find a leak during your tightness test, then yes, obviously it has the, the potential to make it a little bit longer because you've got to start then working out, are we within our permissible limits? Basically, is that leak we've got Okay. For the, for the pipework that we've got, for the installation volume we've got. So yes, it is going to take a little bit longer.

How commonly do you see leaks in pipework?

I would probably say if we did, I know if we did 20 gas safety checks a week, we may find 1 or 2 that are, you know, not, not large leaks. We wouldn't— for me, even with the permissible limits that the current, you know, the old ones with the, you know, your 4 and your 8 millibar depending on the size of the meter. If you had anywhere near 4 millibar, I would be sort of concerned that that's a fair-sized leak, you know, regardless of the size of the meter. I wouldn't be too happy about leaving it, although it passes as long as there's no smell of gas, or it did, you know. And you'll find that's the same way with a lot of gas engineers. A lot of gas engineers don't like leaving any leaks, which is understandable. Even though it passes, it's, it's still not how they, you know, would like to leave it. I would say probably, yeah, out of— if you did, if you did 20 gas sets a week, you'll probably find 1 or 2 might have low leaks up to a millibar, 2 millibar max. Very rarely do you get much more unless there's sort of a serious problem.

Yeah. Even if you're just trying to smell the gas, if it's in a cavity somewhere, there's no—

That's it. Almost impossible if they're running under floors, if they're through concrete floors, you know, if a— and you might get it with old pipework, old barrel pipework, steel pipework, that sort of thing. If it's been in a long time, well, that could, you know, the way they put the pipes together, that stuff sort of corrodes over the years and stuff. So it could be something like that. You'd like to think any leak, you would often, you know, you'd smell it. You'd like to think if you did have a leak, it's in the gas meter cupboard somewhere, which would be an absolute dream, you know, or the appliance itself. The appliance itself, then it's sometimes gas valves don't shut off fully and they can let a very small amount of gas through. Hobs, things like that. The burners can let a very small amount of gas through. But it's so small you detect it on a tightness test, but you may not smell it in a, you know, in a well-ventilated room. So it's going to catch a lot of people out. I think it's going to be a tricky, tricky one with some places. It's going to be almost impossible to run a new gas pipe. Yeah.

Yeah. Without major, major works.

Yeah.

Anything else in summary that would be useful for gas engineers?

I would say really with this, I don't think, I mean, hopefully once people, I say this document, having this on them will give them everything they need to know. There is something that should be highlighted that also is probably people are not aware of, is one of the things that if you cannot isolate the appliances, so for whatever reason there is no way you can isolate an appliance on the, on, then you have to go with worst case scenario, which is basically the largest insulation volume that we're allowed to go to, which is only a 1 millibar drop. All right, so if you can't isolate, you have to assume then it's pipework only. So you haven't got to calculate it if you can't isolate the appliances. You've just got to go straight to tightness testing. And if you've got up to 1 millibar drop or any drop, it's a fail automatically because you can't isolate the appliance. You've technically got pipework only, and that's going to catch people out. That, that because they're going to start looking at it like, well, you've got to go worst case. Well, worst case is 1 millibar, but 1 millibar is only if the appliances are attached. Well, now you've taken the— if the appliances cannot be isolated and they're part of the same system, well, it's— you've got to include it as pipework only. And that is going to not catch people out, but that's going to— I think that's going to cause problems, because if it is the appliance and you can't isolate it, well, now it's sort of got to be included as pipework. And unless you isolate it, unless you fit an isolation. Yeah. So that would be my first protocol before I go to the lengths of saying they need a new gas supplier, would be let's fit an isolation if there isn't one. But for whatever reason you can't fit one, then you've got to go worst case scenario, which is pipework only, even with the appliances attached. And yeah, that could again cause issues.

Okay, well, thank you very much for that. I really appreciate your time and sharing your insights. And that's, um, from Terry, ex-Gas Safe Inspector.

Thank you.