Posts Tagged ‘Newsletter’

Norwegian stave churches: 1000 years old and still standing

11/09/2012

A stave church, or stavkirke, is a timber church with a structural framework of timber staves (beams) resting on timber sleepers and carrying timber wall plates. The wall frames are infilled with vertical planks.

Borgund stave church

The exterior varies from simple and rough-hewn to painstakingly ornate, and in size the churches range from small, shed-like structures – such as Haltdalen stavkirke – to the more imposing Heddal stavkirke, which is the largest of its kind still standing. (At the end of this post, you will find the legend of how the latter was built in only three days.*)

In medieval Norway, the stave frame was the prevalent construction method for churches. There were at least a thousand of them – some sources say as many as two thousand – the length and breadth of the country, built in the 12th and 13th centuries. But by 1650, most of them had disappeared. Following the devastation wrought by the Black Death, many churches fell into disrepair, whilst the Reformation brought a change in the construction, style and use of churches.

Tarred pine shingles clad the steep roof sections

Today, only 28 of the original stave churches remain. Set on stone foundations, the rest of the buildings are entirely made from wood; from the dowels to the roof shingles. It is amazing to see how well some of them have lasted.

The best preserved is Borgund stavkirke in the county of  Sogn og Fjordane, in which most of the existing structure consists of original timbers.

Built from pinewood between 1180 and 1200, it is a striking, darkly ornate structure at the heart of a lush valley. I took the pictures in this post when I visited Borgund last August.

From the interior. In places, rune inscriptions can still be seen.

The intricate carvings, small-format shingles, and black dragons’ heads craning their necks from projecting gable apexes, are miles away from the simple, neutral style we tend to associate with Scandinavian architecture.

Through the centuries, stave churches were preserved by covering the timber in tar. When I visited this summer, the church had just been freshly tarred, making the external wood even darker than normal and lending it a rich, warm scent in the sun.

The external gallery, freshly tarred

The magnificent detailing and impressive longevity of it all made me think of the immense contrast between the church itself and the bleak, sparse living conditions of the people who built it. For farmers and craftsmen eking out a living in a remote Norwegian valley, building such a structure must have been an immense undertaking.

Medieval carvings, beautifully preserved

* There is an old legend about the building of Heddal stave church.

A local farmer, Raud Rygi, wanted to have a new church built. A mysterious stranger came along and offered to do the impossible: to build the church in only three days. His fee for this task was one of three things: either the farmer would have to fetch him the sun and the moon out of the sky, hand him his own heart on a plate, or guess the stranger’s name. Unsurprisingly, Raud chose the third option. He thought he would have plenty of time for name-guessing, as surely nobody could build a church in three days…

However, on the first night, the materials were already in place. On the second night, the steeple was raised. Despairing, and with only one day left before the church would be complete, Raud wandered round the building site at dusk. Suddenly, he heard a haunting voice rising out of the mountain, singing a lullaby: “Hush now, little one, tomorrow Finn will bring you the moon, the sun, and Raud’s heart for you to play with…”

Riddle solved: the builder was Finn, the troll. Raud Rygi’s life was saved, and Heddal had its new stave church.

Runic inscriptions on a church wall

The Old King’s Road, leading up to Borgund stave church

Fire sprinklers in the movies

23/08/2012

After debunking the myths surrounding ventilation ducts in Hollywood, we take a quick look at the frequent faux pas that are made with fire sprinklers.

TVTropes.org observes:

When someone needs to create chaos in a building or just get everyone to leave, they trip the sprinkler system. Just apply a lighter flame, or perhaps a bullet, to one fire sprinkler, and all of the sprinklers on that floor — or even in the entire building – will suddenly kick off. Everyone gets drenched, and there’s a mass exodus from the building.

The only problem with this is that sprinklers do not work that way. Practically all sprinkler systems are of the “wet pipe” type, where the pipe to all of the sprinklers is full of water under pressure, and the only thing stopping it coming out is a heat-sensitive valve in the sprinkler head. Heat it up enough, and the valve pops — out comes the water…read more

Day 25: Fire Sprinkler
Fire safety systems – UK suppliers – ESI.info

Apparently this trope is so prevalent in the media that people now expect sprinklers to go off all at once. This must be a source of real frustration to building services engineers and sprinkler suppliers – has anyone experienced businesses being reluctant to install sprinkler systems because they think even the smallest fire will cause enormous water damage?

Building on Fire! image: Bjorn J on flickr

This idea is corroborated by lo-fi movie mistakes website Zyra.net, which issues this plea to scriptwriters:

It may be a bit inconvenient when trying to write a plot, but really, you’ve managed OK without airships being a dreadful fire risk (they’re full of non-inflammable helium), and if a car goes off the edge of a cliff, it’s acceptable for it to burst into flames after it hits the ground rather than in anticipation just after leaving the cliff edge. So, for a quality story writer, it should be reasonably easy to factor in the truth about automatic fire extinguishing sprinklers!

Day 23: Exit
Emergency exit signage suppliers – ESI.info

Building Services engineering products – ESI.info

Why aren’t we all enjoying a quiet night’s sleep?

31/07/2012

The introduction of Building Regulations Part E in July 2003 represented a big step by which all residential developments in England and Wales had to undergo pre-completion acoustic tests and meet certain airborne and impact sound performance figures. In 2004, building to Robust Details was added to this, providing an alternative method to pre-completion testing to show compliance with the Part E of the Building Regulations. So – nine years on, is everything as quiet as a mouse?

Patrick Dent, AMIOA MEng and Technical Director of Total Vibration Solutions Ltd, explores the issue of noise.

Image by Romana Klee on Flickr

Have these regulations meant that all new build dwellings and those formed from a material change of use are being constructed in a way that provides no noise issues and leaves each and every resident as happy as the proverbial Larry? Well, the simple answer is no. My weeks rarely go by without speaking to an individual who is having noise issues within their newly constructed apartment or house, yet when we investigate their complaint we find that the development met the requirements of Approved Document Part E of the Building Regulations.

So what’s going wrong? Do we need to revise Part E of the building regs? Are we overlooking certain things in the testing? Or do the regulations simply not give a result that the end client deems acceptable?

In truth, there are a wide variety of reasons why we are still encountering noise problems. One factor that caused a great deal of issues originally – although a lot of developers and specifiers are now aware of this trait of certain materials – was the problem of creep. Acoustic underlays and under-screed materials, which offered good acoustic performance initially, would continue to deflect under load over time and not recover to their original thickness. This would result in the resilience in the floor being lost, floors dropping, and floors that met the pre-completion testing initially, suddenly failing six months later.

This is quite an easily rectified problem that can be overcome by developers and specifiers ensuring that they do not use materials that are susceptible to creep. Foams are particularly prone to creep, so any foams used in this capacity should be closed-cell and cross-linked, however any reputable manufacturer or supplier should have test data available on the creep performance of their materials.

The more complex problems come when we investigate noise complaints where there clearly is a noise problem, and yet the development still passes the impact and airborne tests required to comply with Part E of the Building Regulations.

One such example I was made aware of recently involved some luxury apartments where the occupants had got together and complained that the sound insulation in the floors of their apartments were not good enough. An acoustic consultant was called in to independently test the floors. The results gave on average an airborne DnT,w+Ctr of 50dB (Part E requires a minimum of 45dB for new builds and 43dB for dwellings formed by material change of use, which the apartments actually were in this case) and an impact figure LnT,w of 52dB (Part E requires a maximum of 62dB for new builds and 64dB for material change of use). In other words, figures that any developers would be very happy with, and that were comfortably within the requirements of the building regulations.

However, what the acoustician did notice was the incredibly low background noise level. So although the noise levels caused by people walking above wouldn’t be noticed within a building with a more “normal” level of background noise, in these luxury flats, such dramatic but inconstant changes in noise level makes the sound very audible and quite disturbing.

A lack of background noise makes occasional sounds all the more noticeable

This brings us to the fact that an individual’s threshold of hearing and their perception of noise will change depending upon the environment that they are in. Part E of the Building Regulations doesn’t take the background noise level into account – so in this case, the occupants of these luxury flats are left feeling aggrieved at what they perceive as poor sound insulation in their building, whilst the builders would point to the testing that shows they have more than exceeded the requirements. So who is at fault?

Problems with background noise levels aren’t the only issues that we see on a regular basis. There is a widely accepted agreement that the tapping machine used in ISO 140 does not provide an accurate reproduction of the noise produced by footfall. Similarly, the test does not consider the low frequency performance and given that what you are hearing – particularly in dwellings formed by material change of use with timber floors – is caused by the deflection of the joists induced by the footfall, which produces sound at much lower frequencies than 100Hz, the ISO 140 calculation methods ignore it.

AcoustiCORK™ agglomerated cork underlay for impact noise and thermal insulation

So does this mean that the tests are useless and we should completely overturn them? Well, the simple answer is no. In the majority of cases, Part E provides a very good standard to ensure that the end occupant is not disturbed by noise. But here is where we need to be careful. It is a standard. It is the minimum requirements that a building needs to achieve. Certain circumstances, such as a low background noise level, a higher degree of luxury etc., will dictate that the builder needs to achieve a far greater level of sound insulation.

You wouldn’t fit out the furniture of a student hall of residence in the same way you would million pound apartments. Neither should you treat the sound insulation in the same way.

How to choose safety glass

09/07/2012

Specifying the right type of safety glass for your project can be of vital importance. The Standard Patent Glazing Company is an expert in the field: founded in 1902, the company specialises in the design, manufacture and installation of patent glazing systems for contracts anywhere in the UK. Darren Lister provides this useful guide:

Toughened Safety Glass (Safety Class Rating A)

Toughened safety glass (sometimes called tempered glass) is produced by heating annealed glass to approximately 620ºC, at which point it begins to soften. The surfaces of this heated glass are then cooled rapidly. The technique creates a state of high compression in the outer surfaces of the glass and, as a result – although most other characteristics remain unchanged – the bending strength is increased by a factor of up to five times that of annealed glass.
When broken, the toughened glass fractures into small pieces (called dice). As these particles do not have the sharp edges and dagger points of broken annealed glass, it is generally regarded as a safety glass. While these dice may cause minor cuts, it is very difficult to cause a severe injury with them, provided the fragments are small enough.
Toughened safety glass must be cut to size and have any other processing (such as edge polishing or hole drilling) completed before toughening, because attempts to “work” the glass after toughening will cause it to shatter.
All toughened glass has the highest Safety Rating available, which is Class A to British Standard 6206.

Laminated Safety Glass (Safety Class Rating A or B)

Laminated glass consists of one or more panes of glass attached to and separated from each other by means of interlayer materials. Laminated glass is usually made from annealed glass, although it can also be manufactured using toughened, heat-strengthened or wired glass. It is no stronger than the glass it is made from and cracks as easily. However, when laminated glass breaks, the glass fragments tend to adhere to the interlayer material. Although the glass itself may be annealed glass, on breaking, any sharp cutting edges are not generally exposed. The performance of the glass depends very much on the type of interlayer, and there are many different types. The most common interlayer is PVB (polyvinylbutyral) sheet, which usually sticks to the glass very well and produces a high-energy absorbing interlayer of uniform thickness.

  • 6.4mm thick laminated glass obtains a Class B safety rating to BS 6206.
  • 6.8mm thick laminated glass obtains a Class A safety rating to BS 6206.
  • All laminated glass with a PVB interlayer at least 0.8mm thick obtain a Class A safety rating to BS 6206.

Wired Safety Glass (Safety Class Rating C)

This is a product which has been regarded as a safety glass for many, many years. The wires in wired glass tend to hold the glass together when it is cracked. They perform this function admirably when used in roof glazing and, most particularly, in providing fire resistance, but up until recently most of the wired glass products on the market were not classifiable as safety glass to BS 6206. Wired glass is now supplied with thicker and stronger wires to obtain a safety Class C rating to BS 6206.

View The Standard Patent Glazing Company’s beautiful photo gallery of completed work here.

Case study: soundproofing a music room using folding sliding doors

09/07/2012

Doors, by nature, will allow a certain amount of noise to escape. However, there are specialist designs and techniques available to help alleviate the level of audible sound. Here is how Baca Architects and Sunfold Systems solved a musical soundproofing dilemma.

The clients wanted the music room to have an open, airy feel

A client approached Baca Architects, requesting that as part of their home they wanted a music room. This room was to form an important element of their living and leisure time.

A central point of the house was perfect for their requirements for entertaining guests and a key part of the family’s time together, but when it came to the times where privacy was required, they needed to be able to close the doors for recording purposes.

To create the open feel the clients required whilst also having the option to shut off the music area, lead architect Robert Barker wanted to incorporate interior folding sliding doors as an effective and visually appealing solution to the overall project. “Noise transfers so easily through most doors, so it was important for the internal folding sliding doors we used to be flawless, to create a balanced sound level,” he commented.

The music room had to be soundproofed for recording purposes

Robert chose to use Sunfold Systems’ timber range of folding sliding doors, the SFK69 painted in white. This is the highest specification timber system available, and is manufactured from triple laminated solid timber sections. As noise control was key, it was vital that the joints, tracks, frame construction and head detail connectors had no air gaps, to make sure that there was no flanking sound either side.

By using slim-width panels and through the natural slim sightlines of the SFK69, both the structure and the appearance of the internal sliding door system worked well together to achieve the desired effect.

Soundproofing sliding folding doors