Knowledge Bank

Baltic Wharf
1st February 2017
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Case Study – Baltic Wharf

Baltic Wharf is a prestigious development of apartments and hillside homes, situated a short walk from the market town of Totness in South Devon. It is on a site of a working boatyard adjacent to the River Dart. As the second oldest borough in England, this historic market town is reputed to have more listed buildings per head than any in Britain.

The development has been carefully designed to complement the areas existing history and architecture, and new homes here feature natural slate tiles and stone and timber clad finishes.

Baltic Wharf Site Plan

Baltic Wharf Site Plan

The project falls within the South Hams District Council, and all dwellings had to comply with Code for Sustainable Homes Level 4 (CfSH4) under Building Regs Part L 2010. There was also a requirement for 10% of energy requirements to be produced on site by renewable energy sources. We were introduced at planning stage, and invited to meetings with the architect (Stride Treglown) and developer (Bloor Homes), as well as a local consultation process which helped gain planning consent without any objections.

We proposed a specification to achieve low u-values, combining a desired mix of timber frame and masonry units; highly efficient gas heating system with Flue Gas Heat Recovery to each of the 95 units; calculated linear thermal bridging detail; a design air permeability of 4.0 was set (and achieved) on all plots; IG Hi-therm lintels were used; Greenwood System 3 Ventilation was installed; and Waste Water Heat Recovery was installed to selected plots, to ensure 25% improvement on Target Emission rate was achieved.

Baltic Wharf House Design

Baltic Wharf House Design

Further Code 4 compliance was tricky given that private areas were restricted, meaning no provision for Water Butts or Cycle Sheds. Security credits, along with Considerate Constructors, Site Waste Management, Recycling, Composting, and Surface Water credits were all maximised. Daylighting was calculated for each plot, ensuring maximum possible credits.

Low Zero Carbon Savings

Low Zero Carbon Savings

In consideration of High Efficiency Alternative Systems, we found that Solar Photovoltaic was the most viable solution in meeting the 10% energy demand target set by South Hams DC. Given that all plots were positioned to have South facing roof, and with minimal obstruction; we proposed just under 30% of the plots to have a total of 25kWp of PV. All remaining houses were provided with wiring for photovoltaic panels, so residents could upgrade their homes to carbon neutral if desired.

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Briary Energy Viessmann
20th January 2017
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Heating With Ice (Infographic)

Using innovative technology, with their ice storage system Viessmann show us how they can heat and cool a building using ice. To do this, they use the example of Stommel Haus’ award winning home in the Aberdeenshire hills, a development which we were closely involved with.

Making use of this renewable energy source, the system combines an ice storage tank and energy from the air, the sun and the ground to provide a complete home heating system which can heat a building when cold, cool a building when warm and provide a domestic hot water supply.

Freezing is an exothermic process, meaning that as a liquid changes to a solid, heat is released. Viessmann’s system uses this energy released as latent heat, with the potential energy stored in its ice store system.
Viessmann’s standard ice storage comprises of an ice storage tank with a water capacity of approximately 10 m³ and solar air absorbers for installation on pitched or flat roofs.

The solar air absorbers installed on the roof utilise the heat from the ambient air and from insolation during the day and transfer it to the heat pump. They also work to regenerate the ice store if no thermal energy is being drawn by the heat pump.

Utilising ice, the ice store, which is installed in the ground, functions as a source of heat for the heat pump if there is insufficient thermal energy available from the solar air absorbers.

An ice store with a volume of 10 m³ for a detached house can deliver the same amount of energy as around 110 litres of fuel oil and is capable of 10 kW of heating output.
Affordable, dependable, and easy to install, ice storage systems offer high efficiency resulting from the combined use of different heat sources and offer inexpensive. Energy saving natural cooling and heating. In most cases, the systems require no planning permission.
This technology has been adopted by the German manufacturer of eco-homes, Stommel Haus. Using the technology in their award winning three-bedroom Arctic Heartwood Spruce home in the Aberdeenshire hills – Stommel Haus have created the first ever home to utilise this technology in Scotland.
The below infographic shows how Viessmann’s ice store system technology works in Stommel Haus’ eco home.

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Halogen Bulb
10th January 2017
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Halogen Lighting Phased Out / LEDs – No-brainer

In a boost for highly efficient LED lighting; from September 2016, energy guzzling halogen spotlights were phased out across Europe. It is one of several changes, in an effort for European countries to reach their 2020 carbon reduction targets, as per the Energy Efficiency Directive. Ahead of this there is a planned wider halogen bulb ban in 2018, when the multi directional halogen bulbs will also be phased out.

A light-emitting diode (LED) is far more efficient than a halogen bulb; it uses a semi-conductor to convert electricity into light. Halogens meanwhile, work by passing an electric current through a thin filament, which becomes hot and therefore emits light. Only a small percentage of the electricity passing through the halogen light bulb gives of light, whilst the surplus is wasted as heat.

Switching to LEDs can cut lighting electricity bills by 90%. A UK home on an average tariff will pay £126 per socket over 10 years, compared to £16 per fitting over the same period, for LEDs.

LED bulbs have dropped in price by 80% in the last 5 years. A 50W halogen spotlight retailed at approx. £1.50 per bulb, compared to £4.99 for the LED equivalent; however the unreliability of the halogen means it would have to be replaced 8 times to match the lifetime of the LED – you do the math!!!

This change, reducing energy used for lighting, will cut the UKs greenhouse emissions. Also providing lesser environmental impact due to the lower amounts of mercury in LEDs.

This is having an effect worldwide, for example Los Angeles streets now lit solely by LEDs, as is Bayern Munich’s football stadium…and the Sistine Chapel… and you’ve all just lit your Xmas trees with LED lights!!!

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Briary Energy Roof
9th January 2017
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Solar Roof Tiles

Solar Tiles, also known as solar shingles or solar slates, are designed to look like ordinary roof tiles meaning they blend in with the rest of the roof and often considered to be less obtrusive than traditional solar panels being bolted on to roofs.

Tesla, the firm famed for making electric cars and batteries, recently unveiled their new solar roof tiles, which are expected to be rolled out by Sumer 2017. The product, is claimed to ‘look far better than any similar product’, and will be available in a range of styles and colours, being more durable and with better insulation qualities than conventional roofing. The cost of this new product, although not confirmed, is expected to be less than a conventional roof plus traditional solar.

As part of the unveiling of the solar roof tiles, there was also the launch of the ‘Powerwall 2’; a longer lasting home battery which will store any surplus energy from the solar panels. The battery makes the most of the solar tiles, by storing enough unused solar energy to power an average two bedroom home for a full day.

It is a major step forward for Solar PV technology. Much like BIPV (Building Integrated PV), it means larger areas (in this case, whole roofs) can be covered with panels, providing increased production of renewable energy. Solar tiles also provide suitable solutions where a dwelling has a listed status, or is within a conservation area, meaning you cannot bolt on solar panels.

Solar tiles have been available for some years, and although aesthetically pleasing, a stumbling block has been the higher cost compared to traditional panels, meaning a lower return on a solar investment. With Tesla claiming the product to be affordable, beautiful, and seamlessly integrated, we can expect to see more solar roof tiles in the future.

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Briary Energy Stommelhaus
24th November 2016
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Heating with Ice

We have recently been involved in a development utilising the ground breaking ‘Heating with Ice’ technology. Stommel Haus, a German based premium manufacturer of offsite eco houses, with whom we work closely on their UK projects, have installed the Viessmann Ice Store Energy system, to one of their most recent projects, in Aberdeenshire.
Stommel Haus has been manufacturing houses for more than 40 years, with a focus on healthy and natural building material wood, using timber cut from the best quality polar spruce harvested from certified forests. Their slogan ‘Ein Haus wie ein Baum – A House like a tree’ is certainly apt. With their drive for energy efficiency, achieving very high insulation values, and the promotion of a healthy indoor climate; we pride on our links with Stommel Haus. It came as no surprise to us that they were to install one of the first Heating with Ice systems in the UK (and THE first in Scotland). It is a technology which has been heating many Stommel Haus dwellings in Germany, for over 5 years.

The innovative system consists of an underground ice store, solar thermal panels, and a state of the art heat pump, recovering energy from renewable sources, to heat or cool buildings, and supply hot water.
The heat pump takes energy from water in the underground ice store; the water temperature drops as the energy is withdrawn, and in turn the water freezes. When water turns to a solid, it releases latent heat – this latent heat is retained in the ice store.
A ‘heat source management’ system within the heat pump control unit, extracts energy from the ice store, or the solar panels. The ice store also draws energy from the surrounding ground, in order to regenerate heat.
In summer months, the system provides natural cooling. At the end of the heating system, the water in the store is turned to ice, and the heat from the heating system and solar panels is channelled to melt the ice via an extraction heat exchanger, thus cooling the heating circuit within the home.
Other benefits of the Heating with Ice technology are that there is no drilling involved, so no environmental risks, and no permits required. There will be low operating costs due to a high CoP (Coefficient of Performance) of the heat pumps. It will provide a comfortable ambient temperature in a home, regardless of the weather. There is an easy to use control unit, integrated within the heat pump.

viessmann

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Briary Energy WWHRS
7th October 2016
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Tapping into Waste Water Heat Recovery

Briary Energy, being a solutions company, are always striving to find innovative ways of reducing energy use in the home.

One such route we have investigated is Waste Water Heat Recovery Systems (WWHRS). Occasionally, when quoting this technology to clients, we are asked to explain the system, so thought I would use this forum to give a conclusive explanation, and highlight the benefits.

The WWHRS is a copper pipe heat exchanger, consisting of three tubes. Hot waste water from the shower drains away through the inner bore of the heat exchanger. Simultaneously, cold water from the mains is delivered between the inner and outer copper tubes, heating it to around 27°. This ‘pre-warmed’ water is then delivered to the system or combination boiler, as well as the shower taps cold water feed, thereby generously relieving strain from the boiler. The WWHRS will reclaim 60% of heat that otherwise would have been lost down the drain.

Showers are the biggest consumers of water in the homes, using 25% of the total usage. This accounts to over two billion litres of water that Britons are showering away each day, so is a source that would be a waste not to ‘tap’ into.

There are several variations of Waste Water Heat Recovery available, the most common being Showersave Recoh-Vert – see diagram below. This, and other systems, are recognised in the SAP Product Character Database, and can offer 5-7% reduction in Dwelling Emission Rates, depending on size of building.

showersave
Advantageously, compared to alternative technologies such as solar; it works to same capacity all year round, and isn’t aspect dependant. It will reduce energy bills, and help to reduce fuel poverty. It is simple to install, maintenance free, and the life span of the technology is expected to be in excess of over 20 years.

It is a technology which is constantly gaining momentum, with many developers are including it in their specification. Sales have now hit the 50,000 mark across Europe, with 5,000 of these being in the UK.

With a cost in the region of £600, it offers a financially and environmentally viable solution to achieving Part L1a, and enhancing upon Target Emission Rate in SAP.

 

Nick Barker – Briary Energy

WWHRS Ricoh-Vert

WWHRS – dissected to demonstrate functionality

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Briary Energy District Heating
22nd September 2016
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District Heating – Time to Close the Gap

District Heating is a method which, rightly so, is becoming more relevant in today’s climate. Following the update of the Housing SPG, reflecting the alterations to the London Plan, it is mandatory to assess the feasibility of District Heating, to assist towards proposed Zero Carbon residential developments.

District Heating is the supply of heat and hot water to numerous buildings from a central heat source, via a network of highly insulated pipes. It can be used to supply heat to new or existing buildings, from residential to offices or public buildings. Varying in size from covering a whole city, to serving a single apartment block.

Whilst District heating is a relatively new concept to some people in the UK, it is a system which is thriving in Europe. Copenhagen district heating system, deriving from ten CHP plants and 1650km of pipework, is supplying 98% of the city’s heating needs. Throughout Scandinavia it is a common place method, and their power stations offer up to 90% efficiency, far ahead of UK’s best cogeneration schemes. It is also a popular heating method in various other countries throughout Europe.

It did become popular in the United Kingdom after World War II, to heat the emerging large residential estates devastated during the Blitz. The Pimlico District Heating Undertaking became operational in 1950, initially supplying 1,600 social housing units with heat produced from Battersea Power Station. Despite the Power Station closing decades ago, and some of the flats sold privately, the heating infrastructure remains and is still expanding today; but alas, nationwide, our use of the technology pales into insignificance compared to our European neighbours…maybe now is the time to close that gap…

As said, if you are planning a major residential development, within the targets of the London Plan, you will have to consider district heating methods, whether connecting to an existing network, or implementing a site wide CHP, or communal heating network. The London Heat Map provides information on existing district heating systems within London, plus details for new network opportunities, and is a comprehensive tool for developers to meet the decentralised energy policy. Examples of existing heat networks in London include London King’s Cross, the Olympic Park and Stratford City, Citigen, Barkantine Heat & Power, Whitehall District Heating Network, SELCHP, the Bunnyhill energy centre, University college London and Bloomsbury networks, and the aforementioned Pimlico District Heating Undertaking.

London Heat Map

London Heat Map

London’s Underground system vents, supply a constant 25°C of heat all year, and this will be used in the near future, to heat a proportion of the capitals homes. This is another advantage of District heating; once the network of pipes are in place, whatever fuel source is connected at the end of the pipe to produce the heat, can adapt over time; ie replacing fossil fuels with biomass… or using the heat from the Underground.

As well as the positive environmental effect, there are economical benefits, with lower energy costs, and lower management and maintenance costs. There is however, a need for consumers to be well educated on how to get the best out of their system, including billing, communication and operation clarity. Berlin residents, for example, have long been able to request free energy saving consultations if their district energy costs are higher than average. The EU laid down requirements for informative billing in their 2012 Energy Efficiency Directive.

District Heating certainly is a step forward in helping us to become more self-sufficient, and to use locally available energy sources, rather than relying on imported fossil fuels; and with the targets set out in the London Plan, it is a step towards a lower carbon, and lower cost future.

 

Nick Barker – Briary Energy

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timber
11th August 2016
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Eurocodes and Structural Timber

Eurocodes are a set of harmonised technical rules developed by the European Committee for Standardisation for the structural design of construction works in the EU.
They govern the design and calculation process of buildings and all other types of structures, and incorporate geotechnical aspects, structural fire design, situations such as earthquakes, temporary structures and so on.
The purposes of the Eurocodes are:
To prove compliance with the requirements for mechanical strength and stability and safety in case of fire established by EU law
To provide a basis for construction and engineering contract specifications
To provide a framework for creating harmonised technical specifications – the CE marking scheme – for building products.
In total, there are 10 Eurocodes. These are as follows:
EN 1990 (Eurocode 0): Basis of structural design
EN 1991 (Eurocode 1): Actions on structures
EN 1992 (Eurocode 2): Design of concrete structures
EN 1993 (Eurocode 3): Design of steel structures
EN 1994 (Eurocode 4): Design of composite steel and concrete structures
EN 1995 (Eurocode 5): Design of timber structures
EN 1996 (Eurocode 6): Design of masonry structures
EN 1997 (Eurocode 7): Geotechnical design
EN 1998 (Eurocode 8): Design of structures for earthquake resistance
EN 1999 (Eurocode 9): Design of aluminium structures
Each member state defines National Annexes to each standard to take into account local differences concerning geography, climate and traditional building practices. The safety level remains the responsibility of the government of each member state and differs from state to state. In the UK, the Eurocodes are incorporated into British Standards – so, for example, Eurocode 0 is referred to as BS EN 1990.
With the exception of EN 1990, each of the Eurocodes is divided into a number of parts covering specific aspects. All of the codes relating to materials have a Part 1-1, which covers the design of buildings and other civil engineering structures, and a Part 1-2 for fire design. The codes for concrete, steel, composite steel and concrete, timber structures and earthquake resistance have a Part 2 covering design of bridges. These should be used in combination with the relevant Part 1.
In total, the 10 Eurocodes contain 58 parts.
BS EN 1990: BASIS OF STRUCTURAL DESIGN
BS EN 1990, or Eurocode 0, is the central document in the Eurocodes suite, and provides the framework within which design must be carried out. It is the first operational “material-independent” design code, providing the basic principles of structural design in the main construction materials – concrete, steel, masonry, timber and aluminium – as well as covering a range of disciplines, including fire, geotechnical, seismic and bridge design.
At the heart of BS EN 1990 is the concept of “limit state design”. Limit states are the acceptable limits for the safety and serviceability requirements of the structure, beyond which failure occurs. Structural and load models are set up for each limit state and the design is verified by demonstrating that none of the states will be exceeded when design values are added to the model representing various actions, material or product properties, or geometries.
There are two classifications of limit state: ultimate limit states (ULSs) and serviceability limit states (SLSs). ULSs address the potential for collapse, the safety of people and of the structure under the maximum design load. The following ULSs need to be verified:
Loss of static equilibrium of the structure or a structural element
Failure or excessive deformation of a structure or structural element
Failure or excessive deformation of the ground where the strengths of soil or rock are significant in providing resistance
Fatigue failure of the structure or structural elements.
SLSs, meanwhile, deal with the functioning and appearance of the structure as well as the comfort of users. These limits always have to be agreed with the customer. SLSs cover:
Deformations that affect appearance, that cause damage to finishes or non-structural members, that affect user comfort and the functioning of the structure
Vibrations that cause discomfort to users or limit the functionality of the structure
Damage that adversely affects appearance, durability or the functionality of the structure.
Under BS EN 1990, the limit states are related to design situations that the structure might experience during its life. These are classified as persistent, transient, accidental or seismic.
Persistent design situations refer to conditions of normal use. In the case of a highway bridge, for example, this will include the passage of heavy vehicles since the ability to carry heavy vehicles is a key functional requirement
Transient design situations refer to circumstances where the structure is itself in some temporary configuration, such as during execution or repair
Accidental design situations refer to exceptional circumstances where a structure is experiencing an extreme event
Seismic design situations are when the structure is subjected to an earthquake.
BS EN 1990 also classifies variables such as the types of action imposed on the structure. Actions are divided into three classes:
Permanent. These are actions that remain monotonic and will vary by a negligible amount over time – for example, self-weight, fixed equipment, fixed partitions, finishes and indirect actions caused by shrinkage and/or settlement
Variable. These are the actions that do not remain monotonic and may vary with time – for example, imposed loading, wind, snow and thermal loading.
Accidental. For example, an explosion or impact loading.
Variable actions can either be represented by a “characteristic value” or three other design values that incorporate a reduction factor:
The “combination value” takes into account the reduced probability of simultaneous occurrence of the most unfavourable values of several independent variable actions
The “frequent value” is a time-related function and sets an upper limit for the value of the variable action to which it applies
The “quasi-permanent value” is also a time-related function and converts variable actions to equivalent permanent actions in order to derive the creep loading on the structure.
BS EN 1991 ACTIONS ON STRUCTURES PART 1-1
Like BS EN 1990, BS EN 1991 (or Eurocode 1) is relevant to all structural materials, and gives characteristic values for densities, self-weight and imposed loads for different types of building. For imposed loads, buildings are divided into four categories:
A: Areas for domestic and residential activities – such as rooms in residential buildings and houses, bedrooms and wards in hospitals, and bedrooms in hotels
B: Office areas
C: Areas where people may congregate (with the exception of areas defined under A, B and D1))
C1: Areas with tables, etc.
C2: Areas with fixed seats
C3: Areas without obstacles for moving people
C4: Areas with possible physical activities such as dance halls, gymnastic rooms, stages
C5: Areas susceptible to large crowds such as concert halls, sports halls including stands, and railway platforms
D: Shopping areas
D1: Areas in general retail shops
D2: Areas in department stores
The characteristic imposed loads for these areas are shown in the table below:
Category Uniformly distributed load qk (kN/m2) Point load Qk (kN)
A: floors 1.5-2.0 2.0-3.0
A: stairs 2.0-4.0 2.0-4.0
A: balconies 2.5-4.0 2.0-3.0
B 2.0-3.0 1.5-4.5
C1 2.0-3.0 3.0-4.0
C2 3.0-4.0 2.5-7.0
C3 3.0-5.0 4.0-7.0
C4 4.5-5.0 3.5-7.0
C5 5.0-7.5 3.5-4.5
D1 4.0-5.0 3.5-7.0
D2 4.0-5.0 3.5-7.0
Provided that a floor allows a lateral distribution of loads, the self-weight of movable partitions may be taken into account by a uniformly distributed load, which should be added to the imposed loads of floors obtained from the table above.
Snow loads
Snow loads are a variable action and should be assumed to act vertically. They are calculated by first taking the characteristic value of the snow load on the ground. This is usually determined from records of snow load or snow depth measured in well-sheltered areas. The characteristic value is defined as having an annual probability of being exceeded of 0.02.
To determine the snow load on the roof, this characteristic value is multiplied by a snow load shape coefficient, which takes into account whether or not the snow has drifted, the roof shape and climatic conditions. The load is further adjusted using exposure and thermal coefficient factors to address site topography and the amount of heat lost through the roof.
Wind loads
Wind action is represented by a simplified set of forces whose effects are equivalent to the extreme effects of turbulent wind. The fundamental value of basic wind velocity is defined as the 10-minute mean wind velocity with a 0.02 annual risk of being exceeded, irrespective of direction and season, at 10m above ground level in Category II terrain, which is open country with low vegetation and isolated obstacles with separations of at least 20 obstacle heights. While the 10-minute averaging period is the meteorological standard for much of continental Europe, some individual countries use 1 hour, including the UK and Germany. Both these countries have adopted a factor of 1.06 to adjust the measured 1-hour average data to the 10-minute period.
BS EN 1995: TIMBER
In 2010, British Standards Institution withdrew BS 5268 and replaced it with BS EN 1995 (Eurocode 5). The new standard enables the design of a greater range of timber products and solutions and is more flexible than BS 5268.
Ultimate limit state
As outlined above, the structural models in the Eurocodes use characteristic values, which are then reduced by factors. This is especially important in timber design, as BS EN 1995 requires structural engineers to use a modification factor that takes into account the effects of duration of load, moisture content, temperature and any other relevant parameters. A second factor takes into account the possibility of the characteristic value of a material property (for example, strength or stiffness) being less than the specified value and also the effect of scatter around the mean value of the conversion factor.
Deformation
In BS EN 1995, a value for the deformation of a structure or structural member is required at two stages:
When the loading is immediately applied – this is called the instantaneous deformation
After all time-dependent displacement has taken place – this is called the final deformation.
The Eurocode uses a deformation factor to calculate the final deformation of the structure. This factor is dependent on the type of material being stressed, as well as its moisture content. Values for the factor have been derived for timber and wood-based materials at defined environmental conditions when subjected to constant loading at the SLS over the design life. These factors are given in BS EN 1995, Table 3.2.
BS EN 1995 does not give ultimate values for deformation limits, but the National Annex provides recommendations.
Vibration frequency
BS EN 1995 is also concerned with the vibrational serviceability of residential timber-based floors. It includes a method to verify the SLS of vibration in floors with a fundamental frequency greater than 8Hz. This is based on calculating the deflection under a 1kN load (the footfall effect).
Connections – metal fasteners
Steel-to-timber connections listed in the Eurocode include tooth plates, screws (self-driving, tap, stainless, coated), square and round nails, dowels and bolts. Mechanical connection design is based on values for the embedment strength of the timber material and the yielding moment of the fastener, and follows the theory of timber connections set out by KW Johansen in 1949. The characteristic embedded strength depends on the material and type of connection, and this also determines the spacing between connectors. The spacing is often a key influence on the size of structural members.
The design of fasteners should consider the deformation of the connection and the stiffness of embedded connectors – known as the “slip modulus”. In some instances, a more flexible connection is advisable as it tolerates more movement of the structure. However, if the joints are too flexible this will influence the internal forces analysis.
Connections – glue joints
Glue joints should be designed so that the adhesive is stressed in shear, with few, if any, secondary stresses to cause tension.
Glued connections are mainly produced by a manufacturer in a humidity-controlled environment, and cannot easily be done on site. This can lead to problems with transportation, making the project expensive or even unfeasible. The main principle is that the glue line has to be stronger then the connecting timber. The glues for the connection must comply with BS EN 301, which does not permit on-site gluing.
The typical connection is a finger joint. All types of finger joint connections are categorised as very stiff connections, with a brittle failure mode. Those types of the connections are deemed best for redistributing the bending moment and the slip modulus is minimal.
Part 1-2: General — Structural fire design
Fire safety involves prevention, detection, containment and evacuation. The ignition of combustible materials can be prevented by controlling either the source of heat, reducing the combustibility of the materials or providing protective barriers. Careful consideration of design and detailing, insulation and maintenance of the building and its components is essential.
Timber and wood-based materials comprise mainly cellulose and lignin, which are combustible and will burn if exposed to an ignition source under suitable conditions. But this does not mean that timber is an unacceptable material for construction use. Often the opposite is true. When timber burns, a layer of char is created, which helps to protect and maintain the strength and structural integrity of the wood inside. This is why timber in large sections can often be used in unprotected situations where non-combustible materials such as steel would require special fire protection.
There are two methods in BS EN 1995-1-2 for calculating fire influence on a timber element’s resistance. They are the reduced cross-section method and the reduced properties method.
The UK National Annex determines that the cross-sectional properties in fire should be determined using the reduced cross-section method of 4.2.2. In this method, an effective cross-section should be calculated by reducing the initial cross-section by the effective charring depth.
To help designers of timber structures to comply with the relevant Eurocode, Metsä Wood UK has developed Finnwood, a single-member calculation software, available free of charge. Finnwood can be used for the structural calculation of floor joists, roof beams and columns made from Metsä Wood engineered wood products such as Kerto LVL, Finnjoist and Metsä Wood glulam. The software enables designers to freely choose the geometry of the element such as span, support width, slope and loading. After setting initial parameters, it calculates the optimal section size and prints out full structural calculations. It designs according to BS EN 1995-1-1 (Eurocode 5) and its UK National Annex, and has been verified by TRADA Technology. Finnwood can be downloaded from http://www.metsawood.co.uk/finnwood

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29th June 2016
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How to achieve the best possible results in SBEM

Part L2a of the Building Regulations sets the requirements for all new commercial developments when it comes to how efficient they must be.

1. Complete early
Complete your SBEM (Simplified Building Energy Model) early in the design process. Completing before the build starts will ensure that there are no nasty surprises when the development line continues.

2. Build low-U-values

It may seem simple, but it’s worth highlighting: the lower the U value, the less heat will escape. By lowering the U-values, a more economical heating demand for development is likely.

3. Build the most airtight as possible

As with the above, the more airtight a property is the fewer heat flows, leading to lower heating demand.

4. Avoid using electrical panel heaters

Grid electricity is associated with an extremely high CO2 emission rate – just think of all the processes that need to be done to produce electricity and deliver it to the property. Having electric panel heaters makes it incredibly challenging to meet the requirements.

5. Consider ventilation and cooling

Try to ventilate and cool buildings with passive design methods. If cooling is required, consider minimising glazing on façades facing south. You could also choose a high spec solar control glazing to limit the amount of solar gain and then reduce the air conditioning load.

6. Use low-wattage lighting

“Low wattage lighting design” means a design that uses about 5-8 watts per square metre. Also remember to give the lighting design to the assessor, as this will say they don’t have to assign the default figure to this area, something that won’t give the project the credit it needs in terms of the lighting used.

7. Consider daylight controls

One excellent idea when building energy efficiency is to use daylight sensing controls. These automatically dim the lights when a room has adequate daylight. These are suitable for high-occupancy rooms and large glazing areas. Motion sensing PIR controls could also be in places with low transient occupancies like toilets and storage rooms.

8. Keep your ventilation system highly efficient

Aim for low specific fan and high heat recovery efficiencies. Also, ensuring that any ducting is leak-free is essential.

9. Improve your hot-water storage system

If you have a hot water storage system, you should keep to a minimum the amount of heat lost. Choose a well-insulated hot water cylinder with low heat losses.

10. Call the experts

If you have concerns about SBEM calculations, contact Briary Energy today. We ‘re not just a company that inputs your details and leaves you with a problem unless it ‘passes.’ We advise, consult, encourage, and always bring our considerable experience to help you save money on your build.

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