we're here on site now Milton Keynes with MJ electrical to shoot a series of videos on
this beautiful property in this one we're going to discuss the five things that you should know about
installing fire alarms as we see the installation of these smoke and heat alarms from Fire Angel
the last time we were on site with MJ electrical we were installing a Tesla charger and we had
a little chat with the owner of the business Matt about some of the challenges in running
an electrical business but as electricians we all know that we wear many hats and we
need many strings to our boat so what should we be thinking about when we're installing smoke alarms
number one assess the risk before installation you need to design the fire alarm system and
before you design it you need to carry out a risk assessment why does this matter well because every
property is different in terms of design use an occupier an installation in a property with a
high risk of fire occupied by less physically abled individuals needs to respond to a fire
much more quickly than one that's occupied by a physically abled person there's a number of things
to consider for a fire alarm risk assessment and it should be carried out on a room by room basis
after all the likelihood of a fire breaking out here is much lower than the risk of a fire
breaking out here you'll want to consider the likelihood of various things happening
including a fire breaking out the results of this in terms of injury or death how effective
the detection and warning will be in the space the characteristics of the occupant and any potential
ignition sources in the room all of this should be recorded not only as evidence that it's been done
but also so that it can be consulted in the future should any alterations be made or required
for further detailed information on the process of this risk assessment we heartily
recommend getting a copy of this book the practical Guide to Grade-D fire alarm systems
it contains detailed information on how to do risk assessment right number two understand your grades
that leads us nicely onto considering just what a grade D fire alarm system is now there's some
potential for confusion here because there's both a grade of fire alarm system and a category and
they use similar codes first of all is the grade of system which is the type of fire
alarm equipment installed so you'll have noticed yourself that the fire alarm installation that
you'd find in a large commercial property like a hotel or a college has a central control panel and
an image of the zones next to it and that's very different to the interlinked Fire Angel heat and
smoke alarms that we have in this property that's because they are different grades of fire alarm
these used to run alphabetically from A to F with various distinguishing features with D t0 F being
mainly used in domestic settings like this one in the 2020 update to BS5839-6 grades B
and E are no longer defined grade E because they were powered by the mains with no battery backup
which is not a great system and had pretty much been stopped being made by manufacturers
this smoke detector from fire angel complies with grade D which basically means they run
off mains power but also have a battery backup for if the main should fail but you'll notice on
the packaging here the D has a one after it this is because grade d has now been split into two
sub grades D1 and D2 the difference being that D1 is tamper proof and may therefore be used in
situations where tampering is likely for new build domestic properties in the UK at the moment grades
D1 and D2 are the minimum requirement number three understand your categories however confusingly
there's also the category of system to consider as well this relates to how extensive the fire
detection and alarm system is this breaks down into two main categories PD and LD these relate
to what the system is protecting the P stands for property and the L stands for life these are then
further subdivided into subcategories these are LD1 which is the highest level of protection to
include detectors in all circulation areas that form part of the escape routes and in all of the
rooms and areas where a fire could start apart from ones with tiny chances of ignition such
as toilets bathrooms and the like category LD2 covers escape routes and high risk areas such
as kitchens and living rooms of course to provide adequate protection and avoid false alarms you'd
use a heat detector in the kitchen so you don't set the alarm off when you carbonize your toast
and finally category LD3 is the minimum level of protection and this is your circulation areas that
form escape routes like landings and hallways one thing to think about in all of these categories
is that if the loft is being used and contains electrical equipment so if you have a lovely
loft conversion or a new built room up there then you should have a smoke alarm installed
as this should be considered part of an escape route or another situation may be that you have
electrical equipment such as boilers photovoltaic equipment or uninterruptable power supplies in an
unoccupied loft space suitable fire detection equipment should be installed in the space also
because of course a fire breaking out up there won't send smoke down to trigger an alarm until
it's far too late to take action number four supplies there are a number of different ways to
provide an electrical supply to the fire alarm you can run a dedicated circuit in from the consumer
unit to the smokes as long as it's labeled as such at the consumer unit however it's also acceptable
to connect the smoke alarms off a local regularly used lighting circuit this has the advantage that
if the power to the circuit is lost you'll know pretty quickly as the lights won't work as well
it's best practice to keep the smokes on the same circuit as each other for a couple of reasons
one is that it makes safely isolating the smokes easy if they're fed off the same circuit rather
than having one on the upstairs lighting and one on the downstairs lighting there's no room for
ambiguity thinking that you've turned both off and one still being on the other matter is that in a
domestic situation the sounder is usually integral to the detector so that if one device is triggered
it communicates to the other detectors and sounds their alarms too this is usually by means of a
hard wired connection detectors are normally connected to each other via a three core and
CPC cable giving a line a neutral and kind of like a switched line conductor for the interconnection
now you can imagine the harm that could develop by having a conductor connected between two separate
circuits that occasionally went live when alarm was triggered it'd be worse than having a borrowed
neutral however there is an exception to this rule and that's if you're using one of these
clever little devices like this one from Fire Angel it's a smart RF radio module and it allows
the detectors to communicate with each other wirelessly so you'll still need a main supply
to each detector but these could all be wired off of different circuits then you simply clip this
module into the back of the detector and install as usual now if a detector is triggered the radio
module will wirelessly send a message to the other detectors that are paired up in the property and
they'll all be sounded it also allows for other options such as remote reporting of the status of
the alarm sounders via a Fire Angel connect number five commissioning and certification
for many years the smoke alarms were kind of neglected in electrical installation commissioning
hopefully the circuit got tested thoroughly as any new circuit would and are really conscientious
sparks would press the test button on the front to make sure it sounded however now it's important
that the system is commissioned properly using appropriate triggering agents so that's not smoke
from a cigarette or from a match that you've just blown out but rather using an aerosol
smoke and a dispenser if it's required likewise it's important to use the correct piece of kit
to test the heat detectors not just using a naked flame and it's also really important to issue the
correct certification this would consist of an electrical installation certificate as required
by BS7671 for the electrical installation side of the work as you'd expect but also a certificate
for the design installation and commissioning of grade C grade D and grade F systems just rolls
off the tongue the name of that one doesn't it this is a very simple certificate that contains
key information about the client the system the installation the installer and by signing
it confirms that all the relevant testing has taken place as it should be so there you go those
are the five things to consider when installing fire detection and alarm systems as demonstrated
by the Fire Angel devices and if you'd like to know more we really do recommend having a
look at the practical Guide to Grade-D fire alarm systems book and you'll find a link to that in the
description below but as always we want to hear from you were you aware of all the requirements
that we've considered in this video what tips would you recommend to your fellow installers of
smoke and heat alarms as always please leave your thoughts and questions in the comments section
below and all that remains in this video is to say thank you very much for watching