Frequently Asked Questions
- I haven’t had inspection
hatches fitted. What does this mean for me?
- I have heard that there could
be alternatives to having hatches fitted. Is this
- Why is carbon monoxide (CO)
- What should I do if I
experience any symptoms of carbon monoxide
- Why are concealed room sealed
boiler flues an issue?
- Do I have to get inspection
hatches by law?
- How much will inspection
hatches cost me?
- Why didn’t my gas engineer
raise this issue when they visited last time
- What does ‘At Risk’ mean? Can
I still use my boiler?
- I think I have a home warranty
but don't know who it is with.
- My home warranty has expired.
What does that mean for me?
- Where do I get room sensing CO
alarms and what will they cost me?
- Who do I approach to install
- Do I need to fire-rated
- My flue also runs through
neighbouring property, will the engineer need to access their
properties to inspect the flue?
- What if I don’t have
inspection hatches fitted?
- What if I refuse the gas
engineer permission to turn off my boiler?
I haven’t had inspection hatches fitted. What
does this mean for me?
If your gas engineer cannot examine the whole length of the flue
they will advise you, in line with industry guidance, that it is
'At Risk', recommend that you do not use it and will ask your
permission to turn it off. This is assuming that there are no other
indications that your boiler is not safe, regardless of the unknown
condition of the flue.
'At risk' is a risk classification used by gas engineers and means
that your boiler and flue system could become dangerous in the
future, in this case it is used because the engineer cannot examine
the length of the flue to confirm it is safe. As a consumer you are
within your rights to refuse permission for it to be turned off,
however you will be asked to sign paperwork to confirm you accept
responsibility for those defects identified in the system – in this
case, the potential for fumes to escape unnoticed from the
concealed flue into the property.
Your gas engineer can continue to work on your boiler including
servicing it and undertaking maintenance work.
If you have had your boiler serviced since January 2011, your gas
engineer should have made you aware of the need for inspection
hatches, giving you time to consider what action to take.
The law has not changed.
What has changed is guidance to gas engineers in relation to them
being able to examine the flue. There is no legal duty on you to
have inspection hatches or other controls installed. If you choose
not to have them, you should continue to have your boiler serviced
and checked every year by a Gas Safe registered engineer who will
advise that it is ‘At Risk’ (see above).
If you choose not to have inspection hatches fitted, Industry has
developed a safety system which can monitor the void through which
the flue runs for carbon monoxide. This system will cause the
boiler to be shutdown if and when carbon monoxide is detected. Your
registered gas engineer will be able to provide you with further
information on these systems. Inspection hatches remain the
preferred option but the safety shut down system does afford you
with a level of protection against an undetected failure of the
Fitting carbon monoxide alarms are also a good second line of
defence but are no replacement for an engineer being able to
inspect the length of the flue.
You are required, by law, to
have an annual gas safety check carried out, by a registered
engineer, on every gas appliance you provide and on any
flue/chimney. Additionally landlords are required to ensure that
gas fittings and flues are maintained in a safe condition. These
duties require the gas engineer to be able to examine the flue to
check that it is safe. Repositioning the boiler or the flue is an
option, but if this is not viable, inspection hatches are currently
the recommended means by which an engineer can adequately examine
along the length of a concealed flue.
I have heard
that there could be alternatives to having hatches fitted. Is this
Visual examination checks by engineers via
inspection hatches is currently the preferred method recommended
by the industry guidance that explains how to judge that a
flue is working safely and effectively. However, where inspection
hatches are not practicable industry has developed a safety system
which is able to monitor the void for the presence of carbon
monoxide and which cause the boiler to shut down if it is
Speak to your Gas Safe Registered engineer for advice on what
solution may be appropriate for you.
Why is carbon monoxide (CO) dangerous?
CO is a colourless, odourless, tasteless, poisonous gas produced by
incomplete burning of carbon‐based fuels, including gas. It is only
when the gas does not burn properly that dangerous levels of CO are
produced. CO stops the blood from bringing oxygen to cells,
tissues, and organs and can kill quickly. Around 20 people in Great
Britain die each year from CO poisoning caused by faulty gas
appliances and flues.
CO poisoning can easily be confused with food poisoning, viral
infections, flu or tiredness. Symptoms to look out for include
headaches, breathlessness, nausea, dizziness, collapse, loss of
consciousness, tiredness, drowsiness, vomiting, pains in the chest,
stomach pains, erratic behaviour or visual problems.
What should I do
if I experience any symptoms of carbon monoxide
- Get fresh air immediately. Open doors and windows, turn off gas
appliances and leave the house
- See your doctor immediately or go to hospital - let them know
that you suspect carbon monoxide poisoning. They can do a blood or
breath test to check
- If you think there is immediate danger, call the Gas Emergency
Helpline on 0800 111 999. For natural gas in Northern Ireland, call
the Northern Ireland Gas Emergency Service on 0800 002 001.
- Get a Gas Safe registered engineer to inspect your gas
appliances and flues to see if there is a dangerous problem
Why are concealed room sealed boiler flues an
Advances in technology allowed boilers to be
put in a greater variety of positions, not just on an outside wall,
suiting the development of flats and apartments where space was at
a premium. This resulted in some room sealed boilers being
installed in a way that the flue cannot be examined to make sure it
is correctly fitted and safe.
Do I have to get
inspection hatches by law?
No. There is no legal duty
on the consumer to have inspection hatches installed. However,
there is a long-standing legal duty on gas engineers to be able to
examine the flue to ensure it is safe whenever they work on your
boiler. In the majority of cases this will be only be possible
though the installation of inspection hatches. If gas engineers
cannot examine the flue along its length they will advise you that
the installation is ‘At Risk’ and will seek your permission to turn
It is important that this should not deter you from having your
boilers serviced or maintained as this will at least confirm that
the boiler itself is currently safe even if the flue cannot be
confirmed as safe.
How much will inspection hatches cost
It will vary from property to property. It is
recommended that hatches are at least 300mm x 300mm and wherever
possible, be positioned within 1.5m of any joint in the flue
system. Therefore, some properties will only need one hatch, while
others may need more
Basic inspection hatches must comply with the Building Regulations
and are likely to cost from £75, though you may choose to fit more
expensive ones for cosmetic reasons. Costs for the fitting of the
inspection hatches will be extra.
Why didn’t my gas engineer raise this issue when they
visited last time?
If your flue could not be
examined, your gas engineer should have informed you on a previous
visit that your system was ‘Not to Current Standards’, unless there
was evidence of an additional safety issue that would have required
your boiler system to be declared ‘Immediately Dangerous’.
Technical instructions to gas engineers changed from January 2011
following a number of cases where, once inspection hatches had been
installed, faults were found in flue systems. There have also been
several cases where CO from a faulty boiler has been found to be
entering properties from faulty concealed flues. In light of this
evidence, industry organisations have now decided it is right for
gas engineers to classify installations with concealed flues as ‘At
Risk’ for the safety of the occupants.
What does ‘At Risk’ mean? Can I still use my
If your system is ‘At Risk’ its safety cannot
be confirmed and it could become dangerous in the future. Having
inspection hatches installed, which allow for the flue to be viewed
along its length, will mean your system is no longer classified ‘At
Risk’ (as long as there are no additional safety issues found with
the boiler or flue system).
If inspection hatches are not fitted, your gas engineer will advise
you that the installation is “at risk” and turn the boiler off,
with your permission.
I think I have a home warranty but don't know who it is
When you purchased the property your solicitor
should have told you who was providing the home warranty. It is
possible that you have correspondence from the warranty provider.
The main warranty providers in the UK are NHBC and Premier
Guarantee. Depending on the age of the property Zurich Building
Guarantee may have provided the warranty. The contact details for
these are listed on the landing page covering this issue.
warranty has expired. What does that mean for me?
If your home warranty has expired, you or your landlord will have
to meet the cost of the inspection hatches and any defects to the
boiler or its flue. If you receive benefits you may be entitled to
financial assistance. Further details can be found on the Health
and Safety Executive website.
It may still be worth contacting your home builder who may be
willing to assist in some way, or be able to recommend reputable
building services companies to carry out the work.
Where do I get room sensing CO alarms and what will they
Room sensing CO alarms can continue to be
used once inspection hatches have been installed and are
recommended as an additional precaution.
Room sensing CO alarms installed by one of the main energy
companies should cost between £20 and £30. Costs from independent
gas engineers will vary.
Alternatively, you can purchase long life battery CO alarms (to BS
EN 50291:2001) from most DIY stores, supermarkets and high street
stores from around £20 each. If you are installing them yourself
always follow the manufacturer’s instructions on where to fit
Who do I approach to install inspection
A competent builder or building services
company should be able to fit the inspection hatches. The builder
will need to speak to a registered gas engineer on how many
inspection hatches are needed and where they should be
If you do not know a builder, the government supported ‘Trustmark’
scheme should be able to provide advice on how to find a reputable
building company to carry out the work. Go to trustmark.org.uk or phone: 01344
630 804 for further details.
Do I need to fire-rated inspection
It is possible that the original
plasterboard ceiling will have been designed to provide fire
protection; it may also provide acoustic/noise protection too. The
hatches that are fitted need to provide equivalent fire/noise
protection to the ceiling they are replacing. Fire-rated hatches
are more expensive than non-fire rated budget ones. When
retro-fitting inspection hatches it is recommended that hatches
rated to provide a minimum of 1-hour fire resistance should be
specified. Non-fire rated hatches should only be fitted where
professional advice has confirmed they are suitable - such advice
may be available from the original builder or a suitably qualified
[Note: Where advice is not freely available from
the original builder it may well be cheaper to fit 1-hour
fire-rated hatches than to pay for professional advice to determine
whether or not they are required.]
‘Inspection hatches installed to provide access to an existing
chimney system in a void in the majority of cases should usually
have a minimum of one hour fire resistance for residential
buildings with floors no higher than 18m above ground level. The
use of non-fire rated hatches needs to be assessed by a suitably
qualified surveyor to ensure satisfactory fire and acoustic
resisting performance. The following bullet points may provide
additional help in determining the type of inspection hatches you
- Two storey houses and those with fire escape stairs require
robust fire resisting floors and escape routes that usually rely on
the internal linings to maintain integrity for the required length
of time. A fire resisting hatch of some type will usually be
required in these situations.
- In apartments with concrete or timber floors, the plasterboard
ceiling below could be providing fire resisting properties to
either the structural elements or the protected escape routes. In
most situations the suspended plasterboard ceiling will have been
an integral part of the assessed acoustic performance, any hatches
within it will need to maintain satisfactory acoustic performance.
A denser fire rated hatch should provide better acoustic
performance than a non-rated hatch. Therefore In most apartment
block situations a rated hatch is either required or is
- The majority of installations would normally be covered by the
above, but there may be other situations where non-rated hatches
can be used. This will require an assessment from someone that is
suitably qualified and understands the technical aspects of the
In all cases the inspection hatch manufacturer will be able to
confirm the fire resistance and provide a fire test certificate. In
new build situations, the building control body will be able to
advise on the suitability of the inspection hatches.
My flue also runs through neighbouring property, will
the engineer need to access their properties to inspect the
Where the flue also passes through a
neighbouring property the engineer should take all reasonable steps
to ensure overall flue integrity. This will involve making
enquiries with the occupants of the neighbouring property. In these
situations and on the basis of checks of the boiler and the
chimney/flue system in the property containing the boiler are all
satisfactory, reasonable steps need to be taken to gain access to
adjacent property to check overall chimney/flue system integrity.
Gaining access to adjacent property will normally require the full
assistance and co-operation of others to achieve e.g. Housing
Associations, Social Landlords and neighbours etc. Reasonable steps
may be demonstrated by taking the following actions as a
- making enquiries with the occupants of those other adjacent
properties to gain access.
- writing to the occupier explaining the requirement and seeking
arrangements to gain access within a reasonable timescale.
- making arrangements for suitable access to be provided within a
In some cases, despite having taken reasonable steps, access to
the flue in the neighbouring property may not be possible (e.g.
hatches not fitted within neighbouring property or a lack of
response from occupier). When the engineer checks the flue in the
property where the appliance is located there is no evidence of
concern, then having taken reasonable steps to access the adjoining
property (but failed) the engineer’s risk assessment can conclude
(with the appliance remaining operational). However where the
engineer has good reasons to suspect flueing problems it is
essential that the complete length of the flue is checked
(including adjoining property) and the appliance must not be used
unless or until this is done.
What if I don’t have inspection hatches
Provided there are no obvious immediate
safety issues evident gas engineers can continue to work on your
boiler but should advise you that it is “At Risk” and will ask your
permission to turn it off, to ensure they comply with industry
guidance. If you choose not to fit inspection hatches, you should
however continue to have your boiler maintained every year by a Gas
Safe registered engineer and consider using alternative means of
managing the risk of failure of the concealed flue e.g. void
sensing carbon monoxide detection systems (see earlier FAQ for
What if I refuse the gas engineer permission to turn off
The aim of this guidance is to make
consumers aware of important safety issues relating to concealed
room sealed flue systems and carbon monoxide and to set out what
action should be taken to protect those who live in or visit the
property. As a consumer you are free to refuse the gas engineer
permission to turn off your boiler. In these circumstances however
you will be asked to sign paperwork to confirm you accept
responsibility for those defects identified in the system which
could result in a serious incident.