National Energy Code for Buildings (NECB 2015)
National Energy Code for Buildings (NECB 2015) - Transcription
Slide 1
Hello, my name is Elisabeth Girgis. I'm here to speak to you today about the
The National Energy Code for Buildings and the most recent changes to the National Construction Code.
Unlike fire safety, which has been around since the 1940s, the previous energy Codes were not widely adopted until the 2011 NECB.
As of today, the NECB has been adopted in British Columbia, Alberta, Manitoba, Ontario, and Nova Scotia. Saskatchewan and Prince Edward Island have also announced plans for adoption.
Please note that this presentation will focus on the changes from the 2011 to 2015 NECB.
If the NECB is new to you, detailed online presentations are available for the 2011 edition.
A User's Guide is available for the 2011 NECB and will be updated for the 2015 edition.
Slide 2
This presentation is part of a series of 13 presentations on the 2015 editions of Codes Canada.
Before I begin with the technical content of this presentation, I will speak briefly about the code development system.
It is important to note that the model Codes, which are developed by the Canadian Commission on Building and Fire Codes, must be adopted by provincial/territorial authorities to become law.
This may mean that Code requirements enacted by legislation within your province or territory might differ from what is presented here. Please check with your local authority.
Slide 3
It is also important to point out that the National Codes are not a federal regulation.
This means it is not NRC or Codes Canada that decides what goes into the Codes but you!
Codes Canada facilitates an open, transparent, and consensus-based process to come up with improvements.
Over 400 committee members volunteer their time to decide on changes to the next Codes.
All committees are balanced between regulators, industry and public interest so that no single category can outvote the other two.
This process is shown on the slide:
- It typically starts with someone requesting a Code change.
- It continues with technical committees developing proposed changes.
- It involves a public review and the final approval by the Canadian Commission on Building and Fire Codes.
It's a simple process and it depends on your input.
Please go to the Codes Canada website and find out how you can:
- submit code change requests,
- participate in committees, or
- comment on proposed changes during our public reviews.
Slide 4
And before we start, here are some clarifications on the presentations themselves:
- The presentations cover only the changes from 2010/2011 to 2015 Codes and not how to use or interpret the Codes in general.
- The presentations contain only the significant changes - the details are in the handbook. Each presentation contains a reference to the relevant pages in the handbook.
- The presentations stay strictly within the scope of the National Codes and do not cover provincial or territorial variations.
Slide 5
The NECB is structured in a similar manner to the other national Codes.
The slide shows what you will find in Division B - the technical content.
It covers building elements that affect the energy efficiency of a building:
- how the envelope keeps the heat in,
- how a building is lit energy efficiently,
- how air and water is heated, cooled and transferred, and
- how electricity is supplied and used.
While these Parts are prescriptive, Part 8 is the performance section - for computer modeling. It offers a lot of flexibility.
In 2015, changes were made to all Sections of the Code, except Part 7 covering the electrical power systems and motors.
So what's new for 2015?
The most significant of these changes affect energy used for:
- envelope requirements for semi-heated buildings like warehouses and air barriers
- lighting controls and power,
- demand control ventilation for spaces with vehicles, and
- an increased scope for service water.
Handbook pages 63-70
Slide 6
Let's start with Part 3.
The 2011 NECB required airtightness only through qualitative design requirements which were very similar to those in Part 5 of the National Building Code (NBC).
When we look at heat loss in office buildings, we find that approximately 16% of heating and cooling energy is attributable to air leakage.
For multi-unit residential buildings, air leakage can account for 24% of the entire energy consumption. That is truly significant.
You can see at the top in the picture on the right what air leakage looks like by infrared thermography.
The only way to minimize it is to design an effective air barrier system.
The picture on the bottom left shows some of the attention to detail that is necessary to make that happen.
However, testing is the best way to make sure an air barrier assembly performs.
Two new referenced standards in the NECB help to reduce air leakage.
ASTM E 2357 is a universal test method.
It can be used in the laboratory or in the field and can be used to demonstrate compliance for traditional assemblies, such as concrete block masonry with two coats of paint to demonstrate compliance.
An important note here is that for compliance with this test method the air barrier must be tested on the warm side of the thermal insulation because the test method does not take into consideration the durability of the air barrier material.
The ULC S742 standard is a newer Canadian-made standard that includes provisions for the more extreme Canadian climate and that addresses the durability of the material.
This standard is a specification type standard.
Not only does it measure the air leakage of an air barrier system, it also includes performance requirements.
So, once an assembly has been tested and passes the test, it will be called an “air barrier assembly” according to ULC S742.
The ULC S742 standard therefore helps designers and specifiers to easily recognize the level of performance provided by a certain air barrier assembly.
So the result of this change means that requirements to reduce energy loss due to air leakage are now more readily enforceable.
They are the same requirements as in Section 9.36. of the NBC.
Slide 7
The 2011 NECB insulation requirements were based on a temperature set point of 18°C on the inside.
However, some buildings such as the warehouse you see on this slide are continuously conditioned to a lower temperature.
These buildings are now referred to as “semi-heated buildings.”
In a heating climate, this relaxation means acceptable energy efficiency with less costly construction for semi-heated buildings.
To make this work, the 2015 NECB introduced a reduced heating degree-day (HDD) value based on 15°C rather than 18°C.
This could mean less stringent U-values for walls, roofs, floors, fenestration and doors in semi-heated buildings.
Now I'll show you how it works.
Slide 8
Here is how this relaxation is applied.
For example, 100 Mile House in British Columbia has a HDD value of 5030 when based on degree-days below 18°C.
It therefore falls between 5000 to 5999 heating degree-days and is in Zone 7a (same as Calgary), which requires a maximum overall U-value for walls of 0.210. This is about an effective R-value of R-27 in imperial units. Roofs and floors in Zone 7a can have a maximum overall U-value of 0.162, which is about an R-35.
However, if the building in 100 Mile House in British Columbia is semi-heated, the value for heating degree-days below 15°C has a value of only 4040. With that value, the building would fall into Zone 6 and the requirement for walls is now U=0.247. That means insulating to R-24 instead of R-27. This relaxation also applies if the performance path for compliance method is used.
The message here is that the NECB now offers a simpler option for semi-heated buildings.
Slide 9
Before we get to the next change, we will cover some basics about the NECB compliance paths.
First, there is a simple prescriptive path that is like a cookbook approach.
It is a simple approach providing explicit performance requirements for various building systems or equipment types.
You will be familiar with these requirements if you use the NBC Part 9 requirements.
For example in the NECB, gas-fired boilers must have a minimum thermal efficiency of 83% if mid-size, or of an 85% AFUE if very large.
While the prescriptive requirements are simple to follow, they don't offer a lot of design flexibility.
Second - at the bottom - we have the performance compliance route.
In the performance path, the entire design is considered.
It permits the most flexibility and allows for consideration of the whole building energy use.
For example, a “better” building envelope could be used to compensate for a lower performance HVAC system.
Third - in the middle - we have a hybrid called the “trade-off path.”
It gives more flexibility than the prescriptive requirements but is limited to each part.
In other words, you can trade more roof insulation against less wall insulation, but there is no trading insulation against HVAC system efficiency or lighting.
Now - where is the change?
Slide 10
Part 3 of the 2011 NECB had two trade-off paths: a detailed and a simple one.
The detailed trade-off path was based on the whole building performance compliance path of Part 8 with non-building envelope parameters kept constant or specified as defaults.
The problem was that it was complex and required almost as much effort as using the full building modeling (Part 8).
It was therefore removed from the 2015 NECB.
Slide 11
Now for Part 4, Lighting
One of the areas with the fastest innovation when it comes to building energy efficiency is the area of lighting technology and controls.
LED lights are one example of quick market penetration since the previous Code (2011).
A study revealed that the industry is ready for:
- more stringent lighting control requirements, and
- for new requirements in areas where lighting controls were not previously required.
For many spaces in a building, automatic controls are now required to control all or a portion of the lighting in the space.
So what does this mean?
It means that an open office space like the one you see on the slide, that has significant daylighting, will now have more appropriate controls (like the one you see on the right) to switch off the electrical lighting when sufficient daylighting is provided.
This will save electrical energy.
Slide 12
The market study also confirmed that the NECB requirements were:
- not based on contemporary lighting technologies, and
- not harmonized with other international lighting standards.
A bit of background for this slide: (look at the top right)
Illuminance is roughly described as the amount of light per area.
And because the NECB is addressing light fixtures for different building spaces, the requirements are expressed as lighting power density.
It is like maximum power allowances in watts per area for each space.
NRC collaborated with the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) and reviewed recommended illuminance levels from the Illuminating Engineering Society (IES) to assess appropriate lighting power densities and to evaluate modeling methods.
As a result, the lighting power densities and illumination levels in the 2015 NECB are now up-to-date and better aligned with other energy Codes.
Many of the lighting power density values have changed - some increased, some decreased. But overall the total amount of lighting power per area has decreased by 8%, which should translate into energy savings in typical buildings.
The lighting power density values for each space have been combined with control options in one table which is more user-friendly.
Combined with the lighting control changes on the previous slide, the overall results are spaces that are adequately lit in a more energy-efficient way.
The 2011 NECB already had a trade-off path for lighting. There is now a new option to calculate any lighting trade-off.
Slide 13
These are four condensers on a building. They are typically used for air-conditioning.
The NECB requires minimum energy-efficiency performance rating for equipment like this in Part 5 and 6 of the Code.
The required ratings are aligned with other federal regulations and were developed through market surveys to make sure they are not too disruptive for the industry.
The NECB lists the minimum performance requirements for HVAC and service water heating equipment in a table.
What's new?
The table has been updated.
First, new equipment types have been added. For example, cooling towers, condensers and gas-fired rooftop units.
Second, a number of minimum performance ratings for HVAC equipment have been increased.
Slide 14
I don't have to explain what this is!
But if you were to zoom out you would see the speed skating oval in Richmond, British Columbia.
You would also see that the people in the stands were exposed to the propane (or diesel) exhaust of the Zamboni® ice resurfacing machine and other vehicles.
The NECB now addresses spaces where fuel-powered vehicles emit pollutants such as carbon monoxide.
In the past, buildings were equipped with manual on-off ventilation controls.
Very often this meant that the ventilation would be left ON even if no vehicles were running.
In a heating dominant climate like Canada, keeping a specific indoor temperature at the same time as providing 100% ventilation means significant energy used.
The solution? Demand control ventilation! (DCV)
It measures the level of carbon monoxide and changes the level of ventilation accordingly. DCV is common in most indoor garages, and is now required for enclosed semi-heated or conditioned spaces with intermittent use of fuel-powered vehicles or mobile equipment.
Other than arenas, this requirement also applies to parking garages and warehouses.
This change means that building controls will respond to important ventilation needs in a more energy-efficient way.
Slide 15
The 2011 NECB only addressed the energy use for hot service water systems.
But electrical energy is also used to pump and move cold water.
Moving water from one area of a building to the next can represent between 2 to 5% of a building's energy consumption.
For example - as illustrated on the right - booster pumps are used in many high-rise apartment buildings to maintain hot and cold water pressure on the higher floors.
The new requirements:
- reduce short cycling of booster pumps when the demand is low,
- regulate water storage tank volume, and
- introduce pressure-sensing controls.
Just as a note for those of you wondering - water services for firefighting are excluded from these requirements.
Slide 16
Wasting water is addressed by the National Plumbing Code (NPC) through the new objective of Water Use Efficiency.
But the concern for excessive energy use to heat the water is addressed in the NECB.
It was found that the default values for hot water use in the NECB were outdated.
As a result, the 2015 NECB and 2015 NPC now have the same water discharge requirements that reflect current technology.
Specifically for the 2015 NECB, the requirements changed from 9.5 to 7.6 L/min for showers.
And for lavatories, new categories distinguish between private and public spaces.
Health care facilities are now exempt, in addition to applications that were already exempt such as emergency eye-wash stations.
Slide 17
As I explained earlier, Part 8 of the NECB is the Part where computer modellers find the default values and settings for their simulation software that ensures each simulation is consistent with the next.
The performance compliance works by:
- Calculating the energy for a reference building based on the prescriptive requirements in Parts 3 to 7 and the default values in Part 8.
- The energy use for that reference building is then compared to a proposed building model - a specific design - your building.
- The energy use of the proposed building has to be equal or lower than the reference building under the same conditions.
What's new here?
- The default values - that were still from the 1997 version - were updated based on new data so that modelling results reflect today's typical building use.
- Some default values were changed to be consistent with the new prescriptive requirements in Parts 3, 4, 5, and 6.
- And some changes were made to clarify ambiguous or overly restrictive wording in the modelling rules.
Slide 18
Takeaways
- Main takeaways from this presentation are about the changes that were made:New requirements for air barriers
- Relaxation for semi-heated buildings
- Updated daylighting controls and lighting power density requirements
- New HVAC and service water equipment efficiency ratings
- DCV has been introduced for spaces with vehicles
- Scope has changed for Part 6 to address all service water
- Update to the hot water maximum discharge rate
- Updated default values for modeling
Slide 19
I have covered a lot of information in today's presentation. The handbook is a useful resource if you want to review the topics from this presentation in more detail.
It covers the majority of technical changes that were implemented in the 2015 National Building Code, National Fire Code, National Plumbing Code and National Energy Code for Buildings.
The handbook can be purchased on NRC's virtual store as a downloadable PDF or as a hard copy.
Slide 20
Contact Information
| Téléchargement | |
|---|---|
| DOI | Trouver le DOI : https://doi.org/10.4224/40002103 |
| Auteur | Rechercher : 1; Rechercher : 1 |
| Orateur | Rechercher : Girgis, Elisabeth1 |
| Affiliation |
|
| Format | Vidéo, Object d'apprentissage |
| Sujet | Codes et guides; construction; bâtiment; énergie; NRCCode |
| Date de publication | 2015 |
| Maison d’édition | National Research Council of Canada |
| Publication connexe | |
| Langue | anglais |
| Exporter la notice | Exporter en format RIS |
| Signaler une correction | Signaler une correction (s'ouvre dans un nouvel onglet) |
| Identificateur de l’enregistrement | 2a2a3cff-fea1-44c1-8e7e-902ffc810cde |
| Enregistrement créé | 2021-05-04 |
| Enregistrement modifié | 2022-06-21 |
- Date de modification :