Question - Good 4 Gas Detector?

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Yung explorer
28DL Full Member
Aug 28, 2015
I'm considering drain exploration, but i don't know where to find a decent 4 gas detector. Anyone got any recommendations?


28DL Full Member
28DL Full Member
Oct 19, 2013
Wakefield, West Yorkshire
I"m currently using an Altair 4X off an Ebay seller that comes with new certificate. Which lasts for 6 months before retest is required (as for all Gas detectors as i understand it ?)

Whether that"s just H&S legislation for workers in works environment as against personal use i"m not sure @Ojay ?

Although the 4X has a countdown to the next retest date . Not sure if it stops working if you don"t retest it or it just beeps at you like an angry thing lol (suppose i should read the PDF)

Although mine will be going in for retest/service as required. i"ve had enough near misses without a detector not too keep it working correctly and calibrated properly.

Other models are available , but any detector is better than no detector IME ;) Although that said it could aid complacency if it"s not working correctly :eek:

Oxygen Thief

Staff member
Oct 17, 2005
All the 4gas I've seen, and including the one I own, do tell you it's due calibration etc. However, you can override this by calibrating it with fresh air.


28DL Memb3r
Regular User
Jun 6, 2007
the sensors do burn out eventually though, IIRC the O2 is the shortest lived sensor -and a pretty useful one to have as explorers a number of years back found when exploring 'kinder surprise' a straight forward culvert that had been done before, only unknowingly one of the exits had been blocked and O2 levels had dropped horrendously, thankfully their 4gas warned them :thumb.

Sewer Sleuth

28DL Full Member
28DL Full Member
Feb 19, 2016
It's not only gas detectors that need to be calibrated and checked regularly. Just about all safety equipment does. If you're going draining, are you taking an escape set as well?

The Lone Ranger

Safety is paramount!
Staff member
It's not only gas detectors that need to be calibrated and checked regularly. Just about all safety equipment does. If you're going draining, are you taking an escape set as well?
In an ideal world or more like a controlled working environment you'd each have a gas monitor, escape sets, attached to a rescue/pulley system, radio's, a watchman and even a rescue team on stand-by, plus a confined space entry board to monitor you in and out. Never mind the pile of paper - risk assessments, method statements, permit to work, rescue plan, confined space entry procedures, certificates for all the equipment being used, etc. As well as certificates for any lockouts or isolations put in place.

I'm not sure if most of the above makes it any safer if the shit did hit the proverbial fan. An escape set would give you the chance to get out, but they are cumbersome to carry with you all the time and usually just 15 minutes for a portable one.

I tend to check both ends of culverts before entering, you can usually feel a good airflow when in them. Sewers are a different matter and not something I tend to dabble in, I'd have a minimum of a 4gas and bail if I had any doubts.
Likes: Sewer Sleuth


28DL Regular User
Regular User
Oct 24, 2008
There have only been a couple of occasions in sewers where the air quality became a serious risk, both were times before I had a gas sensor and I was lucky enough to realise I needed to get out. Once was in the HF which is usually fine.

I got a Microclip XT new off eBay for around £180. A 6 month calibration costs £60 and it needed another £100 worth of parts last time.

Not cheap but it's reassuring knowing you've reduced the chance of being caught off guard. Having said that I know people that rarely use them and have been fine, just depends if the drain gods decide to shit on you at any given time.
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