EPISODE: 023 - APPROVED DOCUMENT G - SANITATION, HOT WATER SAFETY, WATER EFFICIENCY
- Piotr Bytnar BEng (Hons) MSc CEng MIStructE
- Nov 5, 2024
- 17 min read
Updated: 10 hours ago
BYTNAR - TALKS
EPISODE 023 - APPROVED DOCUMENT G - SANITATION, HOT WATER SAFETY, WATER EFFICIENCY
This episode is for people who want to know more about Approved Document Part G – Sanitation, Hot Water, Safety, Water Efficiency.
You should like this episode if you ask yourself questions like:
Who is responsible for ensuring compliance with building regulations related to sanitation, hot water safety, and water efficiency?
What are the key safety and conservation requirements of Approved Document G under Regulation 8 and Requirement G2?
What exemptions from building regulations are outlined in Schedule 2 and Regulation 9?
How can I ensure a reliable and wholesome cold water supply in compliance with Requirement G1?
What are the water efficiency standards set under Requirement G2, and how do you calculate water usage?
What safety measures are required for hot water supply systems as per Requirement G3?
What are the regulations for providing sanitary conveniences and hand-washing facilities in different types of buildings (Requirement G4)?
What are the bathroom and water discharge requirements in houses and flats according to Requirement G5?
What are the installation guidelines for sinks in food preparation areas and additional hand-washing facilities in compliance with Requirement G6?
This is Bytnar Talks: The Engineer Takes on Construction – Episode 23
Hi, I'm Piotr Bytnar. Each day, I help my clients plan and design building projects through Bytnar Limited, a consulting Chartered Structural Engineers practice.
My biggest passion—and the cornerstone on which I've built my business—is finding clever solutions for construction projects. I am a Chartered Structural Engineer and a budding software developer, so you can rest assured that I will strive to talk about the best practices and the use of new technologies in the industry.
And if you're embarking on a construction project, or are involved in planning, designing, and building the world around us, you'll find this podcast useful.
Approved Document G: Sanitation, Hot Water Safety, and Water Efficiency
Hi there, how are you?Welcome to Bytnar Talks, your favorite podcast on all matters of architecture, engineering, and construction.
It is Thursday, the 4th of July 2024—the USA goes nuts in celebration of their Independence Day—and I'm here, back with you, with the 23rd episode and information on Approved Document G: Sanitation, Hot Water Safety, and Water Efficiency.
Before I start covering the material for this episode, though, let's have a look at what we covered last week.
🌀 Last Week’s Recap – Approved Document F: Ventilation
Last week, I talked about Approved Document F: Ventilation in dwellings and buildings other than dwellings.
In short:
Buildings must ensure adequate ventilation for occupants.
Mechanical ventilation systems must be commissioned to meet required standards.
Exemptions include:
Areas with no regular occupancy,
Storage-only buildings,
Single-dwelling garages.
The Approved Document is divided into two volumes:
Volume One deals with dwellings.
Volume Two covers non-dwellings.
Ventilation must include:
Extraction,
Supply of fresh air,
Prevention of external pollutant infiltration,
Purge ventilation (natural or mechanical).
The performance of the system depends on:
Room use,
Location,
Building air tightness.
Upgrading the envelope of an existing building may impact natural ventilation—so this should be approached holistically.
After installation, the system must be commissioned and tested to current standards, with appropriate information provided to the building owner.
Similarly, for other buildings, the provision of information follows the understanding from Volume One, but with special considerations for specific building types—like, but not exclusively:
Car parks,
Offices,
Congregation spaces,
…and the requirement for isolation of some activities, or the need for air quality monitoring.
🧼 This Week – Approved Document G: Sanitation, Hot Water Safety, and Water Efficiency
In this episode, I’ll move to Approved Document G, and the considerations for:
Sanitation,
Hot Water Safety, and
Water Efficiency.
So without further ado, let’s dive into the text of the Approved Document.
🎵 [Music] 🎵
In this episode, I will talk about the statutory guidance contained within Approved Document G: Sanitation, Hot Water Safety, and Water Efficiency.
The episode will follow the standard format for these materials:
First, I’ll read you the text of the actual regulation,
Then we’ll go section by section, concentrating on the most important parts—well, most parts, really—with some commentary here and there.
The document contains guidance for the discharge of requirement G, and Regulations 36 and 37. It is all contained within seven chapters and some appendices.
So let’s get into the nitty gritty of this Approved Document, starting with the text of the legislation.
📜 Text of the Legislation – Part G
Part G: Sanitation, Hot Water Safety, and Water Efficiency
Requirement G1 – Cold Water Supply
Point 1:There must be a suitable installation for the provision of:
(a) Wholesome water to any place where drinking water is drawn off,
(b) Wholesome water or softened wholesome water to any wash basin or bidet provided in or adjacent to a room containing a sanitary convenience,
(c) Wholesome water or softened wholesome water to any wash basin, bidet, fixed bath, or shower in a bathroom,
(d) Wholesome water to any sink provided in any area where food is prepared.
Point 2:There must be a suitable installation for the provision of water of suitable quality to any sanitary convenience fitted with a flushing device
Requirement G2
Reasonable provision must be made by the installation of fittings and fixed appliances that use water efficiently, for the prevention of undue consumption of water.
Requirement G2 applies only when:
(a) a dwelling is erected, or
(b) a dwelling is formed by a material change of use of a building within the meaning of Regulation 5(a) or 5(b).
This ties in with Regulation 36, really—Water Efficiency of new Dwellings—which states:
Regulation 36
Point 1:The potential consumption of wholesome water by persons occupying a new dwelling must not exceed the requirement in Paragraph 2.
Point 2:The requirement referred to in Paragraph 1 is either:
(a) 125 litres per person per day, or
(b) in a case to which Paragraph 3 applies, the optional requirement of 110 litres per person per day,
…as measured in either case in accordance with the methodology approved by the Secretary of State.
Point 3:This paragraph applies where the planning permission under which the building work is carried out:
(a) specifies the optional requirement in Paragraph 2(b), and
(b) makes it a condition that that requirement must be complied with.
Point 4:In this Part, a "new dwelling" does not include a dwelling that is formed by a material change of use of a building within the meaning of Regulation 5(g).
It also ties in with Regulation 37, which addresses the wholesome water consumption calculation:
Regulation 37
Point 1:Where Regulation 36 applies, the person carrying out the work must give the Building Control Authority a notice which specifies:
(a) which of the requirements in Regulation 36(2)(a) or (b) applies to the dwelling, and
(b) the potential consumption of wholesome water per person per day in relation to the completed dwelling.
Point 2:The person carrying out the work must:
(a) where the dwelling is within a higher-risk building, ensure the notice accompanies the application for a completion certificate in relation to the work,
(b) in any other case, give the notice to the Building Control Authority no later than 5 days after the work has been completed.
Point 3:Where the regulator is the Building Control Authority by virtue of Section 91ZB of the Act (the Regulator Building Control Authority for other work), it must send a copy of each notice it receives under this regulation to the local authority for the area in which the building is situated.
Wow. So that was Regulations 36 and 37—just a short interjection between the requirements of Approved Document G.
Now we’re back into the regulation.
Requirement G3 – Hot Water Supply and System
G3.1:There must be a suitable installation for the provision of heated wholesome water, or heated softened water, to:
(a) any wash basin or bidet provided in or adjacent to a room containing a sanitary convenience,
(b) any wash basin, bidet, fixed bath, and shower in a bathroom,
(c) any sink provided in any area where food is prepared.
G3.2:A hot water system, including any system or other vessel that supplies water to, or receives expansion water from, a hot water system, must be:
designed, constructed, and installed so as to resist the effects of temperature and pressure that may occur either in normal use, or in the event of such malfunction as may reasonably be anticipated,
and must be adequately supported.
G3.3:A hot water system that has a hot water storage vessel must incorporate precautions to:
(a) prevent the temperature of water stored in the vessel at any time exceeding 100° Celsius,
(b) ensure that any discharge from safety devices is safely conveyed to where it is visible, but will not cause danger to persons in or about the building.
G3.4:The hot water supply to any fixed bath must be designed and installed to incorporate measures to ensure that the temperature of water that can be delivered to the bath does not exceed 48° Celsius.
Requirement G3.3 does not apply to a system which heats or stores water solely for the purpose of an industrial process.
Requirement G3.4 applies only when:
a dwelling is erected, or
formed by a material change of use of a building within the meaning of Regulation 5(a) or (b).
Requirement G4 – Sanitary Conveniences and Washing Facilities
G4.1:Adequate and suitable sanitary conveniences must be provided:
in rooms provided to accommodate them, or
in bathrooms.
G4.2:Adequate handwashing facilities must be provided:
(a) in a room containing sanitary conveniences,
or (b) in rooms or spaces adjacent to rooms containing sanitary conveniences.
G4.3:Any room containing a sanitary convenience, a bidet, or any facility for washing hands provided in accordance with sub-paragraph 2B must be separated from any kitchen or any area where food is prepared.
Now, off to bathrooms:
Requirement G5 – Bathrooms
A bathroom must be provided, containing a wash basin and either a fixed bath or a shower.
Requirement G5 applies only to dwellings and to buildings containing one or more rooms for residential purposes.
Kitchens and Food Preparation Areas – Requirement G6
A suitable sink must be provided in any area where food is prepared.
Are you still here? Hello?Good! You are a true, strong listener—and thank you for that!
There is a lot of the text, but as however, it is straightforward, and I will unpack it all here and now, following the guidance hidden within the Approved Document.
Let us start with the responsibility for compliance with the Building Regulations.
In the line of importance, the responsibility is first and foremost vested in the building owner.
Then—if different—in a person initiating the work.Then, people specifying and designing the solution (principal designers), and people executing the work (principal contractors or certified installers).
All involved should be competent in their roles, and the building owner needs to ensure this is the case.
The building owner should also facilitate cooperation between all parts and parties, which often boils down to paying for the proper coordination time of all professionals—or all people involved.
And between all of them, you would think this should be taken for granted……but unfortunately, it has not been the case for quite some time now.
Now, dealing with the limitation on the requirements, in line with Regulation 8, which states that for most requirements, achieving reasonable health and safety in or about and in connection with the particular building is enough.
However, some requirements go beyond health and safety considerations—and in this particular case, this is Requirement G2, concerned with conservation of water.
In general, the system should be proper for use, even if it is extended to buildings that would be otherwise exempt from complying with Building Regulations.
If you want to know what types of buildings are exempt from the Building Regulations, you can find these in Schedule 2 of the Building Regulations, which is connected with Regulation 9.
So let us start with the Requirement G1, which deals with cold water supply.
It mandates that the water is wholesome and is reliably supplied with enough flow rate and pressure, without being wasted, misused, overly used, or contaminated.
Now, the wholesome water needs to be of certain parameters, or from a statutory undertaker or licensed provider who makes sure that those parameters:
are in place,
are guarded.
If it is softened with sodium content higher than the limit, it should be considered softened wholesome water, and it should not be used for drinking or cooking.
Wholesome water does not need to be used for all purposes. So, other alternatives like:
rainwater,
abstracted water from underground,
reclaimed grey water,
or industrial process water—
…it is even encouraged to utilize these instead.
Of course, you need to know what you’re doing, and the installation must be safe and proper for the purpose of use.
Requirement G2 – Water Efficiency
This is all about water efficiency, so expect limits on use wherever you look.
Starting with standards set by the Secretary of State, the standard for the use of wholesome water is:
125 litres per person per day,
or 110 litres per person per day (with optional requirements).
The specification for the system and number of appliances will follow the calculations of use in line with the standard procedures, which are described in detail in Appendix A of this guidance.
The calculation takes into consideration the particular water consumption of any given appliance, so specific technical information from the manufacturers will be handy for the calculation.
All things considered:
water closets,
baths,
tubs,
sinks,
dishwashers,
washing machines,
showers,
water softeners,
waste disposal units…
…you get the notion, don’t you?
Naturally, there will be many variations in the number of any given appliance, so the figures will often be:
averaged between the same type but different model,
multiplied by a use factor,
with the minimum considered use added to it.
We can then subtract all the alternative sources of water that we use, and add the minimum figure for external water use, to get the final total result of use for the given building.
We can also approach the quantum of water use by using a fitted fitting approach, which limits the water consumption of the fitting.
If, however, the limit was to be exceeded, or where there is no proposal of a shower, or a proposal to use a water softener, disposal unit, or other water use appliance, we will need to revert back to the calculation.
The limits for different fittings and appliances are given within the guidance. But, for example’s sake:
185 litres per bath
10 litres per minute for a shower
4.5 litres for a single flush toilet
When we use the fittings approach, it needs to be stated on the notice provided to the Building Control Authority.They like to know, and they like to have it written plainly.
So, the note with:
"Less than 125 L per person per day using fittings approach"…statement will do just fine.
You will wonder: What is the optional requirement for the lesser limit of the water use per person?And it is triggered by the condition of a planning permission for the building.
The Building Control Body will need to be informed of the condition, and the requirements of calculation or use of the fittings approach.But with all lower limits and notifications, the notification is the same as before.
Why is it done?It’s because, although the national minimum stated in the Building Regulations is generally considered sufficient by the Secretary of State, the local capacity of the water system may not be as such—so the limit needs to be lowered in those particular cases.
Requirement G3 – Hot Water Supply and Systems
The Secretary of State is satisfied when:
the right water is heated and delivered properly—meaning wholesome or softened water delivered with no waste, misuse, or overuse.
The hot water storage tanks or heaters need to be safe no matter what, and able to deal with failures in a safe and controlled manner—meaning discharge of water when needed.
The system should not be prone to tampering, boiling water, or changing settings by users, and the setup should be right for the supplied appliance.
Hot water needs to be provided to typical outlets:
baths
showers
wash basins
sinks
Generally, though, wherever needed for hygiene purposes.
Your hot water storage system, either direct or indirect heated, will be considered vented or unvented, and each will be regulated by separate British Standards.
Vented Systems
Should have at least a 90 mm internal diameter vent pipe, positioned at the top (to avoid siphoning).
A thermostat to control temperature,
A heating cut-out device,
A temperature or temperature and pressure relief valve.
Unvented Systems
Will also need at least two fail-safes, and a thermostat.
So: heating cut-out and pressure/temperature relief is the way to go.
Sizes
Small water heaters (up to 50 L storage capacity) with:
a thermostat, and
a pressure and temperature safety device—will be fine.
Up to 500 L tanks and 45 kW power input:
these should be a proprietary package,
and cut-out may be on the boiler.
The system should be marked with all pertinent information, as required, with warnings for the user, the installer, and the installer’s information.
Larger Systems
Systems over 500 L and over 45 kW power input:
must be designed by a qualified engineer,
and contain a thermostat and two safety devices.
Systems of up to 500 L, but more than 45 kW power input:
can be proprietary, in line with appropriate British Standards.
Safety Devices
Safety devices fall under:
Non-self-resetting energy cut-outs—whose sole purpose is to stop the inflow of energy into the tank or being released within.
These can be installed in different locations, but as long as they do the job, they are acceptable.
Then we have:
Temperature relief valves,
Pressure relief valves,
Or a combination of both.
If the system cannot replenish itself with new water, there should not be one provided, and instead an additional cut-off device must be installed.
You see, if there is no supply of fresh water, there would be no way of cooling the internal heating elements—and that may be dangerous.
Notification Requirements
Vented systems and unvented systems:
will either need notification to the Building Control Body,
or installation by a person registered as competent and capable of self-certification.
Electric Water Heating
Whether:
instantaneous,
fixed immersion,
or a storage water heater—
…it will need to follow the particulars of British Standard European Norm 60335.
Solar Water Heating
Abiding by particular standards is allowed, provided an alternative heat source is available, and the system should be rated to appropriate temperature and pressure.
Discharge pipes from safety devices should go through a tundish to allow visual inspection if the valve is in operation. The discharge pipe diameter should be at least that of the safety device, and if manifolded, there should be no inhibition of flow. Factory-fitted manifolds combining safety valve discharge with other flows are allowed.
The tundish should be vertical, have an appropriate air gap, and be located lower than the safety valve and at maximum 600 mm away from it, having a bottom vertical pipe run of at least 300 mm.
Further requirements for the specification of the discharge pipe can be found in the guidance, and it concerns the hydraulic resistance of the pipe and its temperature durability.
If the water temperature in the storage system can exceed 80°C, it should be tempered to 60°C before it goes into the distribution system to prevent scalding. Shower temperature should not be over 48°C, so inline mixing valves may be required.
We need to consider the lower temperature at this point and the frequency of the use of the shower at lower water temperature, as it may increase the risk of pathogen growth.
Workmanship needs to meet standards laid out in British Standard 8000.
Commissioning is required as necessary and must follow approved standards, and follow the Domestic Heating Compliance Guide or CIBSE Commissioning Code M.
Where applicable the notice of completion of commissioning must be given to Building Control.
Requirement G4 – Sanitary Conveniences and Washing Facilities
It is considered sufficient to provide enough of the appropriate type, depending on:
the building,
sex,
age, and
health of users,
…and have handwashing facilities not further than the immediately adjacent room to the sanitary convenience.
Additional regulations will extend the considerations we should put on these—like the Food Standards Agency Code of Practice, or Workplace Regulations, which will have some additional points for us to take on board.
In houses and flats, there should be at least one water closet with handwashing facilities in the room containing the WC or in an adjacent room—so long as it is not a food preparation room, and it should be divided from such room with a door.
It should also be located on the entry storey.
The scale and provision of facilities will depend on building use, and will often be regulated by other legislation and British Standard 6465.
Chemical and composting toilets are allowed if the waste can be removed without impacting living spaces or food preparation areas, and is not subject to floodwater impact.
Any clever cookie trying to use methane in their boiler is not welcome to do so.
Requirement G5 – Bathrooms
All that’s needed is a bathroom with either a fixed bath or a shower, and a wash basin.
Sanitary appliances, space around them, and provision of bathrooms should be according to BS 6465—but at least one for a house or flat needs to be provided.
And if you ever argued with your plumber about where the hot water outlet should be—or if he ever made a mistake and tried to convince you otherwise—it should be on the left side according to regulations.
The discharge of water from sanitary appliances should be through:
a grating,
a trap, and
a branch discharge pipe.
But it may also be through:
a macerator and pump small drainage system,
in line with BS EN 12050,
if there is otherwise no gravity-operated alternative.
Requirement G6 – Food Preparation Areas
A sink is considered essential for good hygiene in the preparation of food.
A dishwasher may be located in a separate room, and that room will not need a separate sink.
In places falling under food regulations, additional handwashing facilities may be needed.
The discharge of water from the sink should be through:
a grating,
a trap, and
a branch discharge pipe.
🎵 [Music] 🎵
So this is it, folks—Approved Document G: Sanitation, Hot Water Safety, Water Efficiency.
Let’s sum it up:
Responsibility for compliance with Building Regulations—as ever—primarily falls on the building owner.
Then, those initiating, designing, and executing the work, including principal designers or contractors.
All parties must be competent, and the building owner must ensure that is the case and that proper coordination is possible.
Regulation 8 emphasizes reasonable health and safety, with specific requirements such as G2 for water conservation.
Exemptions can be found in Schedule 2 and Regulation 9 of the Building Regulations.
Requirement G1 mandates a reliable supply of wholesome cold water with adequate flow and pressure, avoiding waste and contamination.
Alternatives like rainwater or reclaimed greywater are encouraged—if properly installed.
Requirement G2 focuses on water efficiency, setting a standard of 125 L per person per day, or 110 L per person per day under optional requirements.
Calculations based on specific appliance consumption are necessary, considering all water uses and potential alternative sources, or alternatively, going through the fittings approach.
Requirement G3 addresses hot water supply, ensuring it is safely heated and delivered without waste.
Hot water systems must have proper safety measures, including thermostats and relief valves.
Vented systems require a 90 mm vent pipe, while unvented systems need two fail-safes.
Large systems (over 500 L and 45 kW) must be designed by a qualified engineer.
Safety devices include non-resetting cutouts and pressure/temperature relief valves.
Unvented systems require notification to Building Control or installation by a certified professional.
Requirement G4 stipulates adequate sanitary conveniences with adjacent handwashing facilities, considering building type and user demographics.
Houses and flats need at least one WC with nearby handwashing, separate from food preparation areas.
Requirement G5 mandates a bathroom with a fixed bath or shower and a wash basin in houses and flats, with hot water outlets on the left.
Water discharge should follow specific standards.
Requirement G6 requires a sink in food preparation areas, with discharge through grating, trap, and branch pipe.
Additional handwashing facilities may be needed in regulated food hygiene areas.
All installation and commissioning must adhere to approved standards and show safe, efficient, and compliant water systems in buildings.
In the next episode, we’ll move to Approved Document H: Drainage and Waste Disposal.
🎵 [Music] 🎵
I hope you enjoyed this episode and that the consideration of Approved Document G—Sanitation, Hot Water Safety, and Water Efficiency—makes more sense to you now.
If you have any questions, reach out to me on LinkedIn or send me an email—I'm more than happy to help you out.
At Bytnar, we deal with planning, designing, and managing your projects, and we are always glad to facilitate a free initial consultation to steer you in the right direction.
Visit www.bytnar.co.uk and reach out to us—whether your question is “Can you help me with my project?” or “What should I do?”—we will be able to give you a piece of non-obligatory advice.
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If your building is falling apart, we can also help investigate the reasons behind it and provide you with an appropriate strategy, design, and specifications for repair.
Thank you again for listening!Please voice your opinions—I’m waiting for you on LinkedIn, and I want to hear from you.
See you next week!And remember: Bytnar Designs the World Around You.
Toodloo! 👋🎙️
Piotr Bytnar BEng (Hons) MSc CEng MIStructE
Chartered Structural Engineer who deals with the Architecture of buildings. His Master's Studies led him to an in-depth understanding of risk and contract arrangements in construction as well as specialist knowledge in soil mechanics.
He and his team help homeowners and property developers to design and deliver construction projects reducing waste in time and the cost. He believes that the construction project is an iterative process that can be well managed and it is best managed if all the aspects of the project definition and management are dealt with in-house or coordinated by one organisation. His team works to all stages of RIBA and ISTRUCTE stages of work and enables contractors to deliver projects on-site providing risk evaluations, methodologies for execution of works and temporary works designs.
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