How Decibel A-Weighting Works and Why It's Important for Fire Alarms

How to measure LOUD NOISES

If you’ve taken a

look through our Fire Alarms and Ventilation systems (maybe it’s a slow afternoon at the office), you might have noticed that sometimes we give a dB(A) value in the technical information, under something like “sound output.”

This fire alarm sounder has a sound output of 101 dB(A); on the other hand, there’s an extractor fan with less than a quarter of the sound output, at 25 dB(A).

Measuring Noise

dB(A) stands for Decibel A-weighting – it’s a measurement of the level of sound pressure in the air. That measurement is modified so that the measured loudness matches the loudness that is perceived by the human ear as closely as possible.

This is opposed to a straight, physical measurement of the sound pressure in the air; the people in charge of taking the measurements try to ensure that the perceived sound stays reasonably constant in all environments. (Strictly speaking, this isn’t always possible for a huge number of reasons, but it’s close.)

Our examples are human-centric applications, after all; workplace noise measurements are also expressed in dB(A) in order to comply with regulations.

An A-weighting filter de-emphasises the lower frequencies (pitches) of a sound and emphasises those around 3000-6000 Hertz where the human ear is more sensitive.

For the physics geeks in our readership (and we assume there must be a few), Wikipedia has a good primer on the subject of decibel A-weighting, with curves and equations.

This gives an easy, single-number measurement of noise level that we can compare with the noise level in the environment. When we need to install a fire alarm, to carry on with our examples, it should be louder than the ambient noise.

Using Noise

The alarm sounder we mentioned above has a sound output of about 101 dB(A), which is a little bit louder than a newspaper press. The “ultra-quiet” ventilation fan is about as loud as a person whispering to themselves in an art gallery.

The measurement in dB(A) allows a contractor to compare the sound output of a thing with the environmental noise level: if the sound output of an alarm sounder is higher than the general level of noise, then the alarm will be heard. If the source output is lower, then it will be masked.

Sometimes, the distance from the source is also given. This is useful – even essential – for larger environments, where an alarm sounder might be installed far away from someone working at a factory machine, for instance. Generally, as the distance doubles, the sound level in dB(A) is halved. This should be taken into account when installing an industrial alarm system.

Broadly: you’ll want to go as loud as possible with the fire alarms (ideally without damaging anybody’s hearing!), and as quiet as possible with ventilation fans and other such appliances.

It’s an interesting experiment and it opens up a whole new can of worms (as if we didn’t have enough already) – how loud is your office? Your house? Are you using the right appliances for the noise level?

The Silent 100 Extractor Fan Faces the Envirovent Fan Power Challenge

The Silent 100 extractor fan faces the Envirovent "fan power challenge" - will it pass?

 The Silent 100 is the latest fan to undertake Envirovent’s gruelling Fan Power Challenge. It’s a fun video, and full of great information for installers. Did you know that a flat cover is the natural enemy of the extractor fan?

A Silent Fan by Name and by Nature

It’s hard to convey in words just how quiet the Silent extractor fans run, so it’s nice that Envirovent have uploaded some videos. Compared with competing products, the difference is so great that at first, we weren’t sure it was plugged in – the microphone can’t pick up the sound!

Sparks Direct stocks Silent 100 extractor fans, optionally with integrated timers and humidistats. They’re great in bathrooms, utility rooms, and kitchens, where a great deal of extraction is required.

(In the video, the silver model is put to the test: you can purchase one here with a timer and humidistat.)

These fans are extremely reliable – out of all the items we’ve sold, we have had only one return! When it comes to high-power air extraction and humidity control, the Silent 100 is the clear choice for architects, contractors, and ventilation enthusiasts.

Earlier today, Envirovent dropped off a display unit, and we’ll be playing with that in the weeks to come. Keep your eye on this blog for the results!

Tiny Design: Compact Electrical Items and Light Fittings for Small Spaces

As the city populations overtake the number of people living in rural communities, and land prices escalate to ridiculous degrees, the “tiny house” niche is becoming a bona fide movement, with San Francisco reducing the square-footage requirement for its citizens and a 8′ x 10′ (approx. 2.43m x 3.05m) London flat sells for almost £30,000.

Okay, so maybe you don’t need to live in a house quite as tiny as those – but for inhabitants of the big cities there are some useful lessons to be taken from the movement.

It makes sense: with small spaces, there is less to clean, and with the move towards cloud storage it’s becoming more and more possible to free yourself from the mountain of “stuff” – books, desks, racks full of CDs – that was once necessary.

And the smaller the space, the less energy it uses overall!

Celebrity architect George Clarke has been showcasing some amazing tiny spaces on Channel 4 recently, and while we probably wouldn’t

move into one, we took some remodelling and refurbishing inspiration from the tiny spaces scene.

The Practical Elements 

In terms of lighting, maximising daylight is key. If you already live in a place with a huge window, then your work is halfway done. For those of us who aren’t so lucky, we’ll be needing a ceiling light.

With space at a premium, a flush or even a recessed ceiling light is a good idea.

That’s the general “ambient” light taken care of – but what about the fiddly corners in, say, the kitchen, which might even just be a part of the living room? Some under-cabinet lighting will throw some illumination on those tricky areas to help you see what you’re doing!

But what about the aspects we tend not to think about? One area that gets overlooked quite a lot is the ventilation, which can be very noisy – even worse in a tiny space. The 5-inch Airflow QuietAir installed in the bathroom is discreet and near-silent.

The Not-So-Practical Elements

We have talked about the practical aspects of designing a small space, but that’s all meaningless if it isn’t pleasant to live there.

Once the light is sorted out, a large mirror will give the impression of a larger space, and effectively double the illumination in the area. And don’t forget the task lighting – bedroom reading lights are more-or-less essential for relaxation at the end of the day (especially if there’s nowhere to fit a television).

But if there’s a lot of vertical space, why not splash out on a striking pendant like the colourful carafe pendant?

We’d like to hear from anyone reading this in a particularly small space – how do you cope with a reduced floorspace? What kind of design tips do you have for us if we were thinking of moving into a flat the size of a walk-in closet (not that this didn’t cross our mind yet)?

(Images via Did Ya See?, the Tumbleweed blog, and blog.buzzbuzzhome.)

Ventilate Properly in The Home Because the Air Your Breathe Matters!

Some people are OK with a random not-so-good-yet-functioning air extractor fan, while others “don’t care about brand but want a good ventilation at home”. But we all need to know that the effect of not having a good quality air in the home is dramatic.

Most people spend 90% of their time indoors and many times 70% of this time is in our own home! If we have a clean air, a ventilated air, even a purified air at home, we have a chance at living longer and at not being affected in our health. The indoor living environment is crucial to the health of the occupants.

What Air do we have In our Home?

It is a proven fact that half of all illnesses are either caused or aggravated by poor indoor ventilation. In conclusion, what kind of air do we have in our home? Of course, we don’t see with our eyes what’s in the air we breathe, but there lots of stuff in there!

Besides to the general moisture build-up in the home (created from washing, bathing, cooking, breathing, being there), a large compound of many other pollutants and contaminants is present in the indoor air both at work and at home. Here are some of the things we may daily breathe in:

  • Volatile Organic Compounds (VOCs) created from the use of aerosols and formaldehyde’s found in furniture and carpets
  • CO, Carbon monoxide, from smoking and combustion appliances
  • Odours from cooking and pets
  • Humidity and vapors created from cooking, showering, washing and ironing, all these amounting to 16 pints a day in an average family home
  • Allergens from house dust mites
  • Mould spores found in household dust
  • Carbon dioxide from household appliances and people

Without any intention to scare you or myself, it’s pretty nasty. What’s the solution  for all these pollutants in the air? Is there a way to actually live in your own home without being negatively affected by the air in home?

Solution: Correct and Proper Ventilation!

Ventilate Properly in The Home Because the Air Your Breathe Matters!The solution to all these problems is simply to ventilate properly and correctly! In other words, you need to calculate what kind of volume of air your room has and you need to get an air ventilation fan that will insure at least 3-4 changes of air per day in the room.

One of the most recommended ranges of energy saving and low cost air extractor fans is the EnviroVent ENV range. Recently we added the ENV1T12V 100mm low voltage centrifugal fan with timer, ideal for kitchen.

With a quiet operation (you can barely hear it) and with a full IPX4 rating, this fan also comes with a timer module incorporated. Excellent for domestic use and with automatic backdraught shutters, this fan meets all the building requirements!

Note: the above info is inspired from EnviroVent’s own documentation on ventilation.

innovation with style – the new Envirovent Silent 100 Design bathroom fans

The interior designs have influenced the way we choose items for the home from wallpaper to practical electrical appliances.  From cooker hoods to shower curtains, current trends have an effect on what we buy and even in a recession consumers still want to furnish and enhance their homes. For the style conscious certain appliances, such as extractor fans, still provide a challenge.

innovation with style - the new Envirovent Silent 100 bathroom extractor fans; application of the EnviroVent Silent 100 Design bathroom fan

Extractor fans are a necessary part of modern day life. As we construct or refurbish our homes in-line with stringent building regulations to become more energy efficient by adding measures such as cavity wall insulation, loft insulation and double glazing, we effectively  ‘seal –up’ our homes and by doing so create poor ventilation, which can lead to condensation and mould problems. Conventional extractor fans are not ‘fashion friendly’ and for a number of people this is not a problem. However, the consumer who has just spent a small fortune on a fabulous bathroom with a trendy walk-in shower will require something extra special that is pleasing on the eye. EnviroVent have the perfect solution – the stylish SILENT 100 Design.

The SILENT 100 Design is a new range of domestic axial fans suitable for utility rooms and bathrooms available in two colours, white or silver, complete with four smart interchangeable front panel trims in four evocative shades.  By incorporating whisper-quiet silent technology, the presence of the SILENT 100 Design fan promises never to ruin the ambiance of the room it has been installed in.

Innovative Silence – the SILENT 100 Design

The SILENT 100 Design is the result of extensive and scrupulous development by EnviroVent’s R&D team, who have patented a refreshing new concept by developing an extractor fan that is designed to extract the maximum airflow with the minimum noise possible. This is achieved by motors mounted on silent elastic blocks; the elastic blocks absorb the vibrations from the motor and prevent the noise being transmitted into the area where the extract fan is installed. This not only significantly reduces the noise from the extractor fan, but also any noise from the surface that supports the fan.

The SILENT 100 Design has been tested for noise and vibration by ENAC/ILAC, an independent research centre in Europe. Here, a benchmark study was carried out on the market’s most popular domestic axial extract fans to test their acoustic benefits against the patented ‘silent’ technology of the SILENT Range.   Each appliance went through sound power level testing using sound pressure. At the time of testing the results showed that out of all the axial fans tested, the most popular ‘quietest’ model on the market emitted twice the noise level of the equivalent SILENT model.

Continue reading this article via, The New SILENT 100 Design – Innovation with style (on the Envirovent website and the Electrical Wholesaler News). Taken with permission from their website, this article introduces some of the benefits and features of the SILENT 100 Design range of bathroom extractor fans. Read more about these fans via preventing the condensation problems, the SILENT 100 design bathroom fan, or at the Heating and Ventilation articles.