Heatstar Technical Advice Paper - 'New building regulations'

Technical Advice Paper

NEW 2022 BUILDING REGULATIONS

The Technical

take a closer look at the recent changes to the building regulations.

Big changes have arrived. What you need to know!

Team at Heatstar

NEW 2022 BUILDING REGULATIONS

Recently introduced, and applicable to all new projects now presented for Local Authority planning approval, the latest Building Regulations seek to achieve a whopping 30% reduction in carbon emissions over the outgoing regulations – and they will affect indoor pools!

Another step is expected in 2025 to reduce carbon emissions yet further, currently being referred to as the ‘Future Homes & Building Standards’. The proposed 2025 standard is intended to enable a ‘zero-carbon’ dwelling, but that would depend upon electricity supplied from the national grid being decarbonised in the future.

Approved document parts

The elements of the new Building regulations that we will review here are:

Part L

Conservation of fuel and power

Part F

Ventilation

Part O

Overheating

There are separate regulation documents for ‘Dwellings’ and for ‘Buildings other than dwellings’. Domestic and commercial swimming pools will therefore fall under the different categories with different stipulations. Generally, domestic regulations are more stringent than commercial. Whereas previously there were separate documents for newly constructed projects and refurbishment of existing projects, now there are just single documents that describe the differing requirements for both.

Part L ‘Conservation of fuel and power’

The elements of the new Building regulations that we will review here are:

Pool shell thermal insulation requirements

The requirement of meeting a minimum thermal insulation value of 0.25 W/m².K for the pool shell, perhaps surprisingly, remains unchanged. Relying solely upon a typical proprietary rigid polystyrene insulation (0.034 W/mK), 140mm thickness of insulation would be required.

Pool surface area excluded from energy calculations

For both domestic and non-domestic applications Part L contains direct instruction upon how an indoor pool room should be considered as part of the energy efficiency calculation for the whole project; basically that the pool room must comply with the same energy requirements as the rest of the project, with the exception that the area taken up by the pool water surface should be treated as a normal floor, theoretically offering the same thermal insulation value as the rest of the pool surround.

The updated regulation wording is as follows:

When calculating the dwelling primary energy rate, dwelling emission rate and dwelling fabric energy efficiency rate for a dwelling with a swimming pool, the thermal performance of the pool basin should not be included in the calculation. Instead, the dwelling primary energy rate, dwelling emission rate and dwelling fabric energy efficiency rate should be calculated as if the area covered by the pool were replaced with the equivalent area of floor with the same U-value as the pool surround.

This emphasises that a pool room needs to be designed to the same building control standards as any other room in the house – there are no special dispensations.

Thermal insulation changes for buildings

Understandably, the thermal insulation values of buildings are required to improve, as has the air-tightness of the building.

The ‘target’ U-values are now:

Roofs: 0.11, Walls: 0.18, Windows: 1.2, Floors: 0.13

The lower the U-Value, the more effective the insulation.

To achieve these standards solely using proprietary PIR insulation (0.022 W/m K), a typical thickness of 125mm in walls and 200mm in roofs/ceilings and 170mm in floors would now typically be required.

The target for glazing is now near the maximum achievable for double glazing & increased application of triple glazing can be expected.

Maximum boiler water flow temperature

Note: Major implication for swimming pools!

This is about the boiler water heating circuit, which may typically have previously been designed for a flow (outlet pipe from the boiler) of 70°C, with a return temperature of 50°C.

Both domestic and commercial building regulations now stipulate a new regulation that:

All parts of the system including pipework and emitters should be sized to allow the space heating system to operate effectively and in a manner that meets the heating needs of the building, at a maximum flow temperature of 55°C or lower.

So, the maximum flow temperature from a gas / oil boiler or heat pump boiler cannot now be greater than 55°C.

Those who have been involved in applying heat pump boilers for indoor pools will appreciate that low heating circuit flow temperatures can have significant implications for required size of heat exchangers, heating coils and air ducts within the design.

Broadly speaking, all projects are now required to be designed so that they can operate successfully on the low flow temperatures previously associated with heat pump boilers!.

Whilst improved thermal performance of a new building will help, this new requirement will have notable implications, typically increasing the size of air heating coils, air ducting and air flow rates by as much as a 30%.

TECHNOLOGY HIGHLIGHT

‘Cross-flow’ multi-plate heat recuperator

A recuperator is a ‘passive’ device that has no moving mechanical parts and consumes no power in order to function. It relies upon air being passed through it by operation of the fan systems.

The recuperator is a series of many channels. Expelled warm pool room air is passed through a channel and cold fresh air is drawn in through an adjoining channel.

Caution: Going forward, it is clearly vital to ensure that the heating system, pool ventilation unit and air ducting are being designed at the correct heating circuit temperature. The implications of attempting to rectify a fundamental aspect such as this after the project is finished is potentially huge.

Energy is transferred from the warm side into the cold side through thermal conduction via the partitioning ‘plate’ that separates the two air channels. The opposing air paths are not mixed within the device.

Cold outside fresh air

Pre-warmed fresh air into pool room

Warm air from pool room

De-energised cold room air exhausted to outside

Conclusion: Equipment formats that have commonly been used in the past no longer comply with the new building regulation standards

Specific Fan Power (SFP)

Specific fan power is the term used to assess the energy efficiency of a ventilation system in moving air.

These requirements have now been moved (logically) from Part F (Ventilation) into Part L (Fuel & Power)

SFP describes the maximum amount of power necessary to move a pre-determined quantity (volume) of air:

Normally the power is expressed in watts and the air volume in Litres per second.

For example:

1.5 Watts of power, per 1 Litre per seconds of air volume moved = 1.5 W/(l/s.)

This would relate to the maximum power consumption permissible to move the stated quantity of air.

Different SFP ventilation efficiencies are stipulated depending upon the complexity of a particular ventilation system. For example, the SFP for a simple extract fan operated intermittently would be 0.5 W per L/sec, whereas an extract & supply system including heat recovery is permitted 1.5 W per L/sec..

The overall required efficiency has not been improved for the new regulations, but there is now an expectation that a heat recovery device will always be included. Variable speed controller is now required for all domestic systems which provide supply & extraction from the same unit and all commercial systems which have motors rated more than 1100 Watts power.

DID YOU KNOW ?

Heatstar have been producing modern format packaged environmental control systems longer than any other company and were amongst the first to become involved in this specialist field. This experience is evident throughout the product range.

For over 40 years Heatstar have been guiding their clients towards responsible energy solutions, setting the benchmark in an environmentally conscious industry.

Heat recovery provision

Note: Major implication for swimming pools!

The new building regulations introduce a fundamental change in the requirement to capture heat from any warm room air ventilated to outside.

‘Heat recovery’ is the process of capturing heat from any warm pool room air being blown outside the building, and transferring this heat into the cold incoming outside fresh air. For example, a heat recovery efficiency of 73% means that 73% of the heat that would otherwise have been thrown away is captured (and 27% is still lost).

In a tightening of the regulation, it is now a requirement that, if both air exhaust and outside fresh air are provided at the same ventilation unit, then heat capture between the two air passages is now mandatory.

The heat capture achieved must now permanently be at least 73% (up from the previous 70%) and comply with the test procedures of BS EN 308 ‘Heat exchangers’.

Pool ventilation units that merely rely upon the periodic / occasional function of a refrigeration dehumidifier to recycle heat from the exhausted air do not comply with the new regulations.

If a pool ventilation unit exhausts air to outside and also takes in outside fresh air, it no longer complies with current building regulations unless it incorporates a dedicated heat recuperator box or, alternatively, a recuperator box is fitted externally within the air ducting in the plant room.

The ability to incorporate a summer by-pass facility, to neutralise the effect of the heat recovery system when room cooling is required, is also stipulated.

Caution: It is important to ensure that any pool ventilation unit that has exhaust and fresh air duct connections can provide a minimum 73% heat capture between the two at all times, using a recuperator box.

Thermal insulation to services

Building regulations now ‘spell-out’ the typical thickness of insulation required on heating circuit pipes and on air ducts.

For example, 28mm diameter pipework is required to have 10mm of insulation, 35mm diameter pipework 15mm of insulation.

For air ducts, a typical minimum insulation thickness of 21mm (0.025 W/mK) is stipulated, 36mm for air ducts intended for heating and cooling*.

There are no specific insulation stipulations for swimming pool pipe work within the building regulation documents.

* For swimming pool warm air ducts, because of the higher air temperatures involved, an insulation thickness greater than this is normally recommended.

DID YOU KNOW ?

Heatstar have been utilising ‘cross-flow’ multi-plate heat recuperators in their product range to exceed stringent UK building regulations since 2008, and were the first company in the UK to do so.

The combination of the recuperator and dehumidification heat pump in a system such as the Heatstar Phoenix EC offers true dynamic heat recovery for indoor pools with active energy recycling efficiencies of up to 380%.

Regulation 25A: ‘Consideration of high-efficiency alternative systems’

Building regulations now require a formal analysis to be undertaken at the design stage into the feasibility of using high-efficiency alternative systems, such as heat pump boilers and renewables.

Ultimately, a heat pump boiler will potentially reduce the project’s carbon emissions by as much as 60% compared to mains gas, which is clearly very significant. However, that is not to say that the heat pump boiler will result in lower running costs and lower carbon emissions invariably come at the price of increased equipment purchase costs.

A dehumidification heat pump is another approach that can offer notably lower carbon emissions if applied.

Feasible or not, a particular client may, of course, simply prefer lower priced equipment, even though it may result in increased carbon emissions.

TECHNOLOGY HIGHLIGHT

‘Blue-EC’ ultra-efficient digital air fans

Against the consideration that the permanent operation of an air fan motor may represent the largest consumer of energy within an indoor pool, Heatstar systems employs a very special type of digital fan to offer the best possible energy efficiency and, so, the lowest operating cost of any such system.

The digital fan uses a directly driven, backward curved, centrifugal impellor, which features a DC motor coupled to an AC inverter.

Part F ‘Ventilation’

Part F is the document which relates to the provision and control of adequate ventilation and air distribution for a building, for the benefit of the people occupying it. There are no specific stipulations included for swimming pools. However, as with all rooms, there is a requirement to demonstrate how adequate outside air provision is achieved.

‘Dilution rate’ of room air with fresh air

Beyond the fresh air appropriate for occupants, a pool room benefits from a constant requirement for the dilution of chemical related gases / odours and a coexisting requirement to maintain a negative air pressure balance within the pool room, to help discourage migration of pool room air into other rooms or into the structure of the building.

Within the ventilation design this is referred to as the ‘Dilution rate’, being a comparatively small quantity of mechanical ventilation with fresh air, that is typically provided on a continuous basis to the pool room.

A key consideration is that, with a lightly used domestic pool equipped with a surface cover, the dilution rate is sufficiently adequate to achieve much of the dehumidification necessary for the room, leaving the dedicated method of dehumidification often on stand-by.

Therefore, if the dilution rate fresh air ventilation can be provided via a recuperator box, able to capture heat that would otherwise be lost on a continuous basis, then the benefit to overall operating costs is very substantial.

Conclusion: Any ventilation unit equipped with a recuperator box will be able to offer significantly better operating costs, irrespective of the method of primary dehumidification chosen.

Commissioning requirements

The new building regulations maintain the requirement for the formal commissioning of fixed building services, to ensure adequate ventilation and optimum energy efficiency in operation, and contain detailed guidance on the commissioning requirements of the various types of systems.

These special fan feature ‘auto-fan’ technology, whereby the speed and power of the air recirculation fan is managed automatically to enable significant energy savings whenever there is low demand for dehumidification or air heating.

For a domestic pool equipped with a surface cover, there will typically be long durations of low demand and the energy saved by ‘auto-fan’ would be very considerable. Additionally, when the fan is operating on low power, ventilation air noise in the pool room can also be reduced.

Part O ‘Over heating’

Part O is a newly introduced document that seeks to limit unwanted heat gain from too much glazing etc.

It is detailed and considers the geographical location of a project and supports the use of shutters & overhangs etc to mitigate the effect of solar heat gain.

It makes reference to G-values, which is the ability of glass to reflect solar radiation.

Government ‘Standard Assessment Procedure’ (SAPs)

The designers of a building are expected to carry out SAPs calculations to demonstrate compliance with building regulations by achieving the Target Emission Rate (TER) for carbon. The current SAPs version 10.2 is now the required standard for building regulation compliance. The detail involved in these calculations is very exact and dedicated software is utilised. The TER is expressed in kg of CO² produced, per m² of floor area, per year.

SAPs give the government carbon rating for each fuel (gas / electric / oil) etc. The latest carbon intensity for electricity used in calculations is actually lower than that currently achievable and assumes continued decarbonisation of the national grid over years to come.

At 0.136 kg per kWh, electricity is now rated significantly better than mains gas 0.210 kg per kWh, which will advantage the theoretical comparable carbon performance of heating systems utilising electricity, such as heat pumps.

Implications: Operating costs

Everyone will appreciate the significant increases in electricity and gas prices witnessed this year. However, for a modern indoor pool utilising energy efficient equipment, the budgets involved remain comparatively realistic.

Taking energy prices at the current government capped level, for a typical 10m x 5m domestic swimming pool constructed to the new building regulation targets, the following approximate operating costs are possible:

Surface cover used 22 hrs per day: £4000 per annum. No surface cover used: £8000 per annum.

These figures include air heating, pool water heating, ventilation & dehumidification.

They are based upon a ventilation system equipped with recuperator box on exhaust / fresh air and the inclusion of a dehumidification heat pump, to offer an optimum ‘hybrid’ approach.

The effect of improved thermal insulation to the building increases the potential benefit of a dehumidifying heat pump dynamically recycling spare heat back into the pool water. This can significantly improve carbon emission and operating cost, particularly if the pool does not use a surface cover.

To download full copies of all current building control regulations visit www.planningportal.gov.uk or contact Heatstar who can supply copies.

How we can help

At Heatstar we will obviously take all necessary measures to ensure that these new building control regulations do not cause you undue hassle, including:

Fully compliant product options

Heatstar can immediately offer a range of fully compliant equipment options, offering heat capture rates that exceeds the required standard.

Building Regs Compliance Statement

At the quotation stage, we will provide you with a clear statement / assessment of the applicable building control regulation requirements and a compliance report for the proposed Heatstar system.

Commissioning plan

At the quotation stage, we will provide you with a commissioning requirement statement for the proposed pool room system, which can be included within the ‘commissioning plan’ for the whole project.

Specific Fan Performance

We will clearly highlight and confirm the Specific Fan Performance of the proposed Heatstar system.

Pool room structural insulation values

On new projects, we have updated our thermal insulation values to match the requirements of the new building control regulations.

Fuel boiler efficiencies

We have updated our boiler efficiency ratings to match those used within the new regulations.

Boiler flow temperatures

We have updated our LPHW flow temperatures and heat output ratings to match those required by the new regulations.

Thermally insulated swimming pool shell

Our heat load calculations make allowance for the benefit of stipulated thermal insulation requirement.

Unit commissioning

We will continue to provide free unit commissioning and generate a commissioning report in line with the format required under the new regulations.