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CSA B45.7-11 (2016) – Technical Guide to Flush Tanks and Flush Valves for Plumbing Fixtures
Understanding the Requirements for Flush Tanks and Flush Valves Under the Canadian Plumbing Code
CSA B45.7-11 (2016) is a key standard in the Canadian plumbing industry, specifying the requirements for flush tanks and flush valves used with water closets, urinals, and related plumbing fixtures. As part of the CSA B45 series, this standard ensures that these components meet strict criteria for performance, durability, and water conservation. This article provides a detailed overview of the standard’s scope, technical requirements, implementation aspects, and compliance considerations.
Scope of CSA B45.7-11 (2016)
This standard applies to flush tanks (both gravity and pressure-assist types) and flushometer valves (flush valves) intended for installation in residential, commercial, and institutional plumbing systems. It covers design, materials, construction, performance testing, marking, and water efficiency. The standard is referenced by the National Plumbing Code of Canada and many provincial codes, making it a mandatory requirement for plumbing fixtures installed in new construction and renovations. It also includes provisions for backflow prevention to protect potable water supplies.
Technical Requirements
CSA B45.7-11 (2016) sets out comprehensive technical specifications to ensure reliable and safe operation. Key areas include:
Materials and Construction
All components must be constructed from materials resistant to corrosion, dezincification, and degradation from potable water and common cleaning agents. Acceptable materials include brass, stainless steel, and approved engineering plastics. Internal seals and gaskets must withstand long-term exposure to water and normal cycling.
Performance and Testing
Flush tanks and valves must pass rigorous testing for flush volume, flow rate, seat leakage, endurance cycling (typically 100,000 cycles for valves), and backflow prevention. The standard specifies test pressures and acceptable leakage limits.
Water Conservation
In alignment with North American water efficiency goals, the standard mandates maximum flush volumes: 6.0 L per flush for single-flush water closets, 4.2 L for high-efficiency dual-flush models, and 1.9 L for urinals. Flush valves must also meet minimum flow requirements at reduced supply pressures.
| Parameter | Requirement |
|---|---|
| Maximum flush volume (water closet – single flush) | 6.0 L (1.6 gpf) |
| Maximum flush volume (water closet – dual flush) | 4.2 L (1.1 gpf) |
| Maximum flush volume (urinal) | 1.9 L (0.5 gpf) |
| Operating pressure range (flush valves) | 138–550 kPa (20–80 psi) |
| Minimum flow rate at reduced pressure (138 kPa) | 0.05 L/s (0.8 gpm) |
| Endurance cycling (valves) | 100,000 cycles without failure |
| Seat leakage test | No visible leakage after 15 minutes |
Backflow Prevention
Flush tanks must include a ballcock or fill valve that complies with ASSE 1002, while flushometer valves must incorporate an ASSE 1037 listed backflow preventer or equivalent. These devices prevent back-siphonage under vacuum conditions.
Marking
Each product must be permanently marked with the manufacturer’s name or trademark, model number, date of manufacture, flush volume in litres and gallons per flush, and the certification mark of a recognized accredited agency (e.g., CSA). Instructions for installation and maintenance must accompany the product.
Implementation Highlights
Successful application of CSA B45.7-11 (2016) in the field requires attention to several practical aspects:
- Supply pressure verification: Flush valves require adequate supply pressure (usually 172–550 kPa). Installers should measure static and dynamic pressure before installation.
- Fixture compatibility: Flush valves and tanks must be matched to the specific bowl design. Using a valve with excessive flow may cause splashing or incomplete waste removal.
- Water level adjustment: Gravity tanks need correct water level setting to ensure proper flush volume and prevent continuous running.
- Freeze protection: In areas subject to freezing, flush valves and tanks must be installed with insulation or heat tracing per code requirements.
When retrofitting older installations for water efficiency, always verify that the flush valve or tank is compatible with the existing fixture and supply system. Many modern retrofit kits allow upgrading to higher efficiency without replacing the entire fixture.
Do not install flush valves on systems where the static pressure exceeds 550 kPa (80 psi) unless a pressure-reducing valve is installed. Excessive pressure can cause internal leakage, damage to components, and premature failure.
Compliance and Certification Notes
CSA B45.7-11 (2016) is recognized by regulatory authorities across Canada. Compliance is typically verified through third-party certification by agencies such as CSA Group, who perform initial product testing and periodic factory inspections. Only products bearing the appropriate certification mark (CSA, cCSAus, etc.) are accepted by most plumbing inspectors and building officials.
Plumbing contractors, engineers, and building owners should consult the latest edition of the National Plumbing Code as well as any provincial amendments to confirm current adoption of the standard. Non-compliant products may be rejected during inspection, leading to costly rework and delays.
Using products certified to CSA B45.7-11 (2016) provides assurance of performance, water efficiency, and compliance with Canadian plumbing codes. The certification mark is clear evidence of conformity.
Installation of uncertified flush tanks or flush valves in a code-regulated building can lead to permit violation, non-compliance orders, and potential liability for the installer or owner if a failure causes property damage.
Q: Can a flush valve certified to CSA B45.7-11 be used with any water closet bowl?
A: Not necessarily. The flush valve must be matched to the bowl design and flush volume rating. Always consult the manufacturer’s specifications for compatibility.
A: Not necessarily. The flush valve must be matched to the bowl design and flush volume rating. Always consult the manufacturer’s specifications for compatibility.
Q: Does CSA B45.7-11 require 6 L maximum flush volume for all new toilets?
A: Yes, as of the 2016 reaffirmation, the standard limits flush volume to 6.0 L for single-flush and 4.2 L for dual-flush toilets. Older larger volume products are not compliant.
A: Yes, as of the 2016 reaffirmation, the standard limits flush volume to 6.0 L for single-flush and 4.2 L for dual-flush toilets. Older larger volume products are not compliant.
Q: How can I verify that a flush tank is certified to CSA B45.7-11?
A: Look for the CSA mark on the product or its packaging. The certification number can be verified through the CSA product listing database.
A: Look for the CSA mark on the product or its packaging. The certification number can be verified through the CSA product listing database.
Q: Are pressure-assist tanks covered under CSA B45.7-11?
A: Yes, the standard covers both gravity and pressure-assist flush tanks, provided they meet the performance and safety requirements.
A: Yes, the standard covers both gravity and pressure-assist flush tanks, provided they meet the performance and safety requirements.