rainwater harvesting alberta - safety codes · pdf fileharvesting systems ... eau non-potable...
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Rainwater Harvesting
In Alberta
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3 Year Research Project at University of Guelph
• What Rainwater Is • Permitted Rainwater Uses In Alberta
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• Rules And Regulations • Anatomy Of A Rainwater Harvesting System
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What Is Rainwater? Rain That Falls On The Roof Of A Single
Family Dwelling
What Rainwater Is Not.
Rain That Falls Anywhere Else
What Can You Use Rainwater For In Alberta?
• Toilet and Urinal Flushing
• Sub-surface Irrigation
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Codes
• Alberta Building Code
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• National Plumbing Code
National Plumbing Code
• Support for underground horizontal piping • Pipe trench backfill • Hydraulic load for roofs or paved surfaces • Hydraulic load on storm or combined building drains
or sewers • Connection of overflow from rainwater tank • Pipe system sizing and capacity • Permitted rainwater outlets • Thermal expansion • Backflow prevention
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Alberta Building Code
• Design data for selected locations in Alberta (conveyance pipe systems)
• Plumbing system and fixtures
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Standard - CSA
• B64 • Backflow Prevention
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Regulations
• Alberta Private Sewage Systems Standards And Practices • Sections 2.5, 4.2
• Tank installation, insulation, etc.
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• Alberta Occupational Health And Safety • Confined Spaces
Guidelines - CSA
• Installation requirements • Pumps • Separation between potable and non-potable
systems • System testing • Non-potable component marking • Water treatment
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B128
Guidelines – CSA (cont’d)
• B128 • Tanks
• Suitable for burial • Access • Pipe connections • Draining • Venting • Overflow
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Guidelines
• Stormwater Management Guidelines For The Province Of Alberta • On-site infiltration systems
• Alberta Guidelines For Residential Rainwater Harvesting Systems
• Canadian Guidelines For Domestic Reclaimed Water For Use In Toilet And Urinal Flushing
• Local Authority Having Jurisdiction • Local Health Authority
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Interested Government Departments
• Alberta Municipal Affairs • Alberta Environment and Sustainable
Resource Development • Alberta Health Services
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Rainwater Quality Codes, Standards And Guidelines
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•NONE
Anatomy Of A Rainwater Harvesting System
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• Catchment Area
• Conveyance Network
• Storage Tank(s) • Overflow And Stormwater Management
• Distribution System • Water Filtration And Treatment
• Potable Water Make-Up And Backflow Prevention
Catchment
width
1 mm of rain on 1 m2 of roof = 1 Litre 18
length
Conveyance Network
CATCHMENT AREA
EAVESTROUGH
DOWNSPOUT
DOWNSPOUT TO PIPE TRANSITION
STORAGE TANK
CONVEYANCE PIPE
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Conveyance System
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• Eavestrough • Slope toward storage tank
• Downspouts • Locate as close to storage tank as possible • Seal transition between downspouts and
conveyance pipe
• Conveyance Piping • PVC SDR35 – usually 4” Ø – size in accordance with
the building code and local regulations • Slope – 0.5% - 2% • Rated for UV exposure
Storage Tank
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Storage Tank Sizing & Placement
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Size
Location
Material • Water usage • Water demand • Volume of water to be stored • Catchment area • Rainfall pattern and volume • Conveyance system loss
• Space • Inside/Outside • Above ground/Underground • Downspout location(s) • Overflow location • Easements/Rights-of-way • Utilities • Access
Cost
• Concrete • Fiberglass • Plastic
• Tank • Plumbing • Electrical • Installation • Transportation • Permits
Weather • Drain for winter • Insulation
Suggested Tank Sizing
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Rainwater Demand (L/day)
Optimum Cistern Capacity (L) Roof Catchment Area (m2)
50 100 150 200 250 300 350
400
50 5,000 5,000 2,000 2,000 2,000 2,000 2,000 2,000
100 2,000 3,500 3,500 3,500 3,500 3,500 3,500 3,500
150 2,000 3,500 3,500 3,500 3,500 5,000 5,000 5,000
200 2,000 3,500 3,500 3,500 3,500 5,000 5,000 5,000
250 - 3,500 3,500 3,500 3,500 3,500 5,000 5,000
300 - 2,000 2,000 3,500 3,500 3,500 5,000 5,000
350 - 2,000 2,000 3,500 3,500 3,500 5,000 5,000
400 - 2,000 2,000 3,500 3,500 3,500 5,000 5,000
450 - 2,000 2,000 2,000 3,500 3,500 5,000 5,000
500 - - 2,000 2,000 3,500 3,500 5,000 5,000
Edmonton: 350mm annual rainfall
Overflow & Stormwater Management
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• A Rainfall Event May Provide More Water Than the Storage Tank Can Hold. Therefore the Excess Water Must be Disposed of in a Safe and Approved Manner
• How and Where Can the Water be Disposed Of?
• Applicable Codes and Regulations • Stormwater Management Guidelines • Type of Lot • Year Lot Was Developed • Current Stormwater Management Techniques
Above Ground Tank Overflow
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Discharge to grade
Storage Tank
Underground Tank Overflow
STORAGE TANK
Soak-Away Pit
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Storm Drain
Distribution System
• Moving The Water To The Desired Locations In A Safe And Approved Manner
• Distribution System Components
• Pump And Controls • Pressure Tank • Distribution Piping
Pumps Submersible
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Jet
Pressure Tanks
Jet Pump
Pump & Distribution System
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Calculating Pump Flow Rate
30 Adapted from Residential Water Systems: Goulds Pumps Technical Data, Water Products. 2007. ITT Corporation, White Plains, NY.
Indoor Fixtures Minimum Flow Rate
Toilet 2.7 LPM [0.7 GPM]
Urinal 2.7 LPM [0.7 GPM]
Outdoor Fixtures Minimum Flow Rate
Sub-surface irrigation system
Varies (consult Supplier/
Contractor)
Rainwater Pressure Piping
• 100 mm separation of potable & non-potable pipes
• Pipe and Outlet Markings: – Outlet label: graphic (see right) or text – Purple pipes (or stripe) – Pipe labeling: – Label must be 5mm height, repeated at
1.5m intervals for pipes
WARNING: NON-POTABLE WATER — DO NOT DRINK
AVERTISSEMENT : EAU NON-POTABLE — NE PAS BOIRE
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Rainwater Quality & Treatment
Pre-Storage Treatment: Filtration
Located in eavestroughs and downspouts 33
Pre-Storage Treatment: Diversion
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Pre-Storage Treatment: Sedimentation
Access risers
Overflow line
Pump outlet line
Rainwater inlet line
Low-level make-up line
Electrical conduit
Level sensors
SEDIMENTATION TANK
STORAGE TANK
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Post-Storage Treatment
Contaminant Treatment Devices/Options Available
- turbidity - total suspended solids - bacteria > 0.2 microns
• Particle filter (100/50/20/5 micron) • Rapid sand filter • Slow sand filter • Membrane filter
- microbiological contaminants (viruses, bacteria and protozoa)
• Ultraviolet (UV) light • Chlorine • Ozonation • Slow sand filter • Membrane filter
- hydrogen sulfide - organic matter - manganese - iron
• Activated carbon • Ozonation • Particle filter (100/50/20/5 micron) • Slow sand filter • Reverse Osmosis • Ultrafiltration & chemical addition
Particle filter (100/50/20/5 micron)
Ultraviolet (UV) light
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odor taste color
Irrigation system
Toilet
Non-potable water pipeline
Municipal pipeline to
potable fixtures
Make-Up System
Solenoid valve (N/C)
Air gap
N/O
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Backflow Prevention
• Backflow - flowing back of or reversal of the normal direction of flow of water
• Backflow Prevention Device - device that prevents backflow
• Cross-connection – any actual or potential connection between a potable water supply or system and any source of pollution or contamination and includes any by-pass, jumper connection, removable section of pipe, swivel or changeover device and any other temporary connecting arrangement through which backflow may occur.
38 Source: City of Guelph, 2009. Backflow Prevention. http://guelph.ca/living.cfm?smocid=1975
Backflow Prevention
• Reduced Pressure Backflow Preventer (RPBP) – Most Expensive – Requires annual testing – Discharges water
• Double Check Valve Assembly (DCVA) –Annual testing –No water discharge
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Hose bib Irrigation
system
Toilet
Washing machine
Non-potable water pipeline
Municipal pipeline to
potable fixtures
Hot water tank
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What’s Wrong With This Picture?
Make-Up System
Air gap
Rainwater to distribution
Mains water
Rainwater from tank
Solenoid valve
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Item to be inspected Frequency CSA B128.B
Recommendations Additional Recommendations
Roof, gutters, downspouts
6 months Inspect; clean gutters, ensure no blockage.
Trim overhanging branches Sweep debris off roof, as necessary Check in winter for ice build up in gutters/pipes
Filter systems 3 months
Inspect; clean or replace filter as required
Check if rainwater and debris is bypassing filter Assess for frost damage
Storage tanks 12 months* Inspect and clean* as necessary. Check for leaks and repair as necessary.
Excessive settling of tank or moisture in soil around tank may indicate leak *Cleaning the tank annually is not generally recommended. Some biofilm in the tank may help to improve tank-stored rainwater quality.
Pumps and pressure tanks
12 months Inspect and verify operation
Inspect components inside of tank for corrosion or degradation; Inspect electrical splicing Ensure pump is not overheating or cycling on and off too frequently, or when there is no demand 42
Item to be inspected Frequency CSA B128.B
Recommendations Additional Recommendations
Backflow preventers
12 months Following CSA B64.10
Make-Up Systems 6 months Inspect float switches for proper positioning and to ensure they are not tangled Ensure electrical splicing is in tack Simulate float switch action to test solenoid valves
Post-storage treatment
6 months Inspect and verify correct operation.
Overflow system 12 months Discharge to grade – ensure no erosion or entry of bugs/debris/rodents Discharge below grade – check for signs of water damage to hatch or inside access riser, or water discharging at air gap or downspout to pipe transition
Labels and signage 12 months Inspect and replace as necessary.
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Rainwater Harvesting
In Alberta