Technical Presentation explaining how siphonic (syphonic) drainage works and benefits from using this efficient roof drainage system. Contact info@hydromax.com for further information.

1. HydroMax™ Siphonic Drainage
Leaders in Siphonic Drainage

2. Topics Covered
 Brief History of Siphonic Drainage
 General Principles of Gravity Rainwater Drainage
 Principles of Siphonic Drainage
 Benefits and applications of Siphonic Drainage
 Installation and Maintenance

3. Introduction to Siphonic Drainage
• Prior to March 2007, there were no comprehensive product and design
standards for siphonic drainage.
• As such siphonic drainage was promoted by suppliers in different formats with
various slants aimed at their own offerings
• The HydroMax focus is on offering high quality, sustainable products with
highly accurate and user friendly design software
• Our approach is to dispel the “smoke and mirrors” educate how they work in
accordance with the current British and/or American Standards
• Technical Support to Design Engineers and Registered Installers
3

4. Siphonic Drainage – Brief History
• Concept invented in Finland by Olavi Ebling in late 1960’s
• First major installation in Sweden in 1972.
• Unregulated Industry Grew through 1980’s
• UK Government Commissioned Research during the 1990’s
(Refer HR Wallingford SR 463 & SR 473)
• European Standard BS EN 12056-3 introduced in 2000
(1st Standard to include a section for Siphonic drains)
• 2005 – ASME A112.6.9 Siphonic Drain Test issued in USA
• 2006 – Singapore Standard SS 525 includes siphonic drainage
• 2007 – Comprehensive Siphonic Drainage Standards
published in UK and USA (BS 8490 and APSE 45)
4

5. What is HydroMax™
Siphonic Roof Drainage?
HydroMax™ is an innovative solution which
utilises the power of a natural siphon to create
a high-performance roof drainage solution.

6. Why use HydroMax™
Siphonic Roof Drainage?
HydroMax™ is an Engineered Solution which
provides many Technical Benefits
HydroMax™ offers cost savings
normally ranging from
25% to 45%!

7. What is wrong with Traditional
Gravity Drainage Systems?
Traditional Gravity drainage systems work
but they are inefficient and have a number
of factors restricting performance.
7

8. Restrictive Factors of Gravity Drainage
1. The water flow-rate is dictated by the gradient available
(this gradient also restricts the distance a pipe can travel).
2. Multiple rainwater pipes in locations largely dictated by the
gravity hydraulics rather than design team choice.
3. Gravity drains require ⅔ air to transport ⅓ water.
4. Vortex formation within vertical gravity pipes results in the
water being transported in an inefficient spiral motion rather
than straight through the pipe.
5. The driving force is only the depth of ponding or ‘head’ of
water above the roof drain.
8

9. “High Performance” Gravity Drain
(from Manufacturers web-site)
Gravity 10” Drain – Depth = 7.3” to Discharge 1500 GPM
(250mm Drain – Depth = 185mm to Discharge 95 l/s)

10. HydroMax 125mm (5”) Drain
Equivalent Flow
(95 l/s – 1500GPM)
Half the Diameter
Half the ponding
depth of the Gravity
drain
125mm Drain – Depth = 95mm to Discharge 95 l/s

11. Vertical Gravity pipes run ‘full’ at
only 1/3 water
⅓ water in annular flow
⅔ air core

12. Horizontal (Sloping) Gravity pipes
run ‘full’ at only 2/3 water

13. Typical Traditional Gravity Drainage System
Multiple Downpipes
Drainage under Building Floor
Extensive Underground Drainage
Sloping Underground Drainage makes for
difficult routing to attenuation/harvesting

14. Principles of Gravity Drainage
Vortex motion
A large amount of Air
is required to move a
small amount of water.
Extremely Inefficient
Annular Flow
Water adheres to pipe wall
Central Air Core
14

15. Siphonic Drainage
Why is HydroMax™ different from gravity drainage?
No Air!
Pipes run 100% full bore

16. Principles of HydroMax™
Siphonic Drainage
• The Siphonic Roof Drain eliminates air entering the
pipe promoting water filled pipework
• The full bore of the pipe work carries the rainwater
• Water, without air, accelerates down the vertical
downpipe, creating negative pressure and naturally
generating a high performance siphonic flow
• The full height of the building provides the energy for
this highly efficient Rainwater Drainage Solution
16

17. Siphonic Drainage - How it works
The inducer on the roof
drain prevents air ingress
- gh
and so
PAtmos Rainwater falling down the
vertical pipe accelerates,
creating negative pressure

18. Siphonic Drainage - How it works
- gh
PAtmos
More Height = Greater Negative pressure

19. Siphonic Drainage - How it works
- gh
PAtmos
Greater Negative Pressure = Higher Flow Rates
The full height of the building provides the energy
for this highly efficient Rainwater Drainage Solution

20. Siphonic Drainage - How it works
HydroMax Siphonic Systems are self-draining
therefore the pipes are empty before a rainfall event
Roof or Gutter HydroMax
Roof Drain
Tail-pipes
Horizontal collector pipe
Downpipe
Discharge

21. HydroMax System with Tailpipes primed
HydroMax Roof Drain
Roof
Pressure
Tail-pipes
Horizontal Collector Pipe
Drop pipe
Discharge

22. Priming of Main Pipe Work
Stage 1 - Wavy or Gravity flow
Air above water
Gravity flow in pipework

23. Priming of Main Pipe Work
Stage 2 - Plug flow
Plug of water filling whole pipe at high
velocities which achieves self-cleansing.
Air pockets driven down pipework
Tests have shown that self-cleansing can be achieved at as
low as 10% to 15% of the design rainfall rate.

24. Priming of Main Pipe Work
Stage 3 - Bubble flow
Water filling whole pipe
Air bubbles in suspension carried at high velocity

25. Priming of Main Pipe Work
Stage 4 - Full-bore flow
No more air entry – Air within Pipe now Fully Purged
Water filling whole pipe

26. Fully Primed HydroMax System
Negative Roof or Gutter HydroMax Roof Drain
Pressure
Tail-pipes
Horizontal Carrier Pipe
Downpipe The full height of the building
provides the energy for this
Discharge highly efficient Rainwater
Drainage Solution

27. Principles of HydroMax™ Siphonic
Eliminate Air Ingress
Pipes run Full-Bore with
Water
Building Height provides
energy for High Self-
Cleansing Velocities
Extremely Efficient
27

28. HydroMax™
Siphonic Roof Drainage Video
Click Here
28

29. HydroMax™
Simulation of
Non-Maintained Roof
Click Here
29

30. Siphonic Roof Drainage System
High Performance Roof Drains
No Drainage
Under Building
Flexible,
Downpipe
Positioning
Significant Reduction in Route to Harvesting
Underground Drainage or Attenuation

31. System Comparison
Traditional HydroMax
Gravity Siphonic
air core
water in annular flow
water
air core
No
Air
water
water
31

32. Traditional Gravity Solution
530 metres Pipework
Diameters 160mm to 450mm
60m
100m
HydroMax Siphonic Scheme
360 metres HDPE Pipework
Diameters 56mm to 200mm
32

33. HydroMax System Termination
Manhole or Catch Pit to have Grate Cover
Note: British Standard BS 8490 states the size of
free area for the Grate should be twice cross
sectional area of siphonic pipe. American ASPE
Technical Design Standard 45 does not dictate the
size of vented area.
Siphonic pipework should enter manhole chamber
33 above the drain invert and be clear of any standing
water to ensure free discharge

34. HydroMax Siphonic System Termination
Vertical Siphonic
Important: Pipe
Below Grade Drain must be
vented and sized to take the Offset
volume of discharge under (if required) to
Gravity flow conditions. line up with below
grade pipe
Do not size to match siphonic
Pipe diameter.
Flex-Seal
flexible,
expansion
coupling

35. HydroMax Siphonic System Termination
Important:
If siphonic drainage is utilised to drain part way down a
high rise building –
A siphon break point must be adequately vented to
atmosphere at the point of transition to gravity flow.

36. HydroMax Siphonic System Termination
Ventilated to Siphonic flow
Atmosphere
Break to Gravity
Recommended Vent size flow
being Two-Thirds
Gravity Pipe size
(two-thirds air to one third
water in the gravity pipe)

37. Suitable Projects for Siphonic Drainage
Retail Chains
37

38. Suitable Projects for Siphonic Drainage
Royal Ascot Racecourse Stadia
Ricoh Stadium and Arena, Coventry
Stadium of Light, Sunderland

39. Suitable Projects for Siphonic Drainage
Dundrum Retail Shopping Malls with multi-level Car Parks
313 Orchard Road, Singapore

40. Suitable Projects for Siphonic Drainage
Commercial Office Buildings Accident Fund, Lansing
E-Tek Flagship Trinidad Stryker HQ, Newbury

41. Suitable Projects for Siphonic Drainage
Accommodation/Hotels/Prisons
Student Accommodation, Wembley
Johnstone County Ibis Hotel, Singapore
Detention Center

42. Suitable Projects for Siphonic Drainage
Hospitals Forest Park Medical Center, Dallas
Mercy Hospital, Des Moines, IA

43. Suitable Projects for Siphonic Drainage
Apartment Blocks
Podium Decks

44. Suitable Projects for Siphonic Drainage
Green Roofs

45. Suitable Projects for Siphonic Drainage
Siphonic Drains installed at
waterproofing membrane level
Green Roofs
45

46. Suitable Projects for Siphonic Drainage
Airports
Gimhae South Korea

47. Suitable Projects for Siphonic Drainage
Warehousing & Distribution Centres
47 110,000m² for Tesco

48. Suitable Projects for Siphonic Drainage
Manufacturing Plants
48

49. Suitable Projects for Siphonic Drainage
Flagship Projects
Scottish Parliament
49

50. Suitable Projects for Siphonic Drainage
Flagship Projects
Masdar City MIST 1B,
Abu Dhabi
50

51. HydroMax Siphonic Products
50mm Balcony Siphonic Roof Drain
This is a special drain
for multi floor balcony
drainage.
The drain has a built in
Anti-Backflow device.
Flow Rate
Max. = 1.5 l/s
(Litres per Second)
51

52. HydroMax Siphonic Products
50mm Terrace Siphonic Roof Drain
Flow Rate
Min. = 1.5 l/s
(Litres per Second)
up to
Max. = 25 l/s
52

53. HydroMax Siphonic Products
75mm Siphonic Roof Drain
Our Metric series of drains come in a range
of models for compatibility with all roof types
Flow Rate
Min. = 1.5 l/s
(Litres per Second)
up to
Max. = 25 l/s
53

54. HydroMax Siphonic Products
75mm Siphonic Overflow Roof Drain
Our Metric series of Overflow drains come in a
range of models for compatibility with all roof types
Flow Rate
Min. = 1.5 l/s
(Litres per Second)
up to
Max. = 25 l/s
54

55. HydroMax Siphonic Products
125mm Siphonic Roof Drain
Our Metric series of drains come in a range of
models for compatibility with all roof types
Flow Rate
Min. = 10 l/s
(Litres per Second)
up to
Max. = 100 l/s
55

56. HydroMax Siphonic Products
Range of Accessories for Our Metric Series of Drains
• Leafguards
• Gravel Guards
• Car Park Drains
• Bespoke Accessories
56

57. Wade-HydroMax Siphonic Products
3” Siphonic Roof Drain
Our North American series of drains have all been tested to
ASME 112.6.9:2005 – IAPMO certified (file number 5305)
Flow Rate
Min. = 23 GPM
(Gallons per Minute )
up to
Max. = 415 GPM
57

58. Wade-HydroMax Siphonic Products
4” Siphonic Roof Drain
Our North American series of drains have all been tested to
ASME 112.6.9:2005 – IAPMO certified (file number 5305)
Flow Rate
Min. = 75 GPM
(Gallons per Minute )
up to
Max. = 750 GPM
58

59. Wade-HydroMax Siphonic Products
5” Siphonic Roof Drain
Our North American series of drains have all been tested to
ASME 112.6.9:2005 – IAPMO certified (file number 5305)
Flow Rate
Min. = 120 GPM
(Gallons per Minute )
up to
Max. = 1300 GPM
59

60. Wade-HydroMax Siphonic Products
6” Siphonic Roof Drain
Our North American series of drains have all been tested to
ASME 112.6.9:2005 – IAPMO certified (file number 5305)
Flow Rate
Min. = 160 GPM
(Gallons per Minute )
up to
Max. = 1800 GPM
60

61. Wade-HydroMax Siphonic Products
3”, 4”, 5” and 6” Siphonic Roof Overflow Drain
Our North American series of drains have all been tested to
ASME 112.6.9:2005 – IAPMO certified (file number 5305)
C.I. No-Hub Minimum Maximum GPM
K factor
Outlet GPM Inflow Inflow
3” 0.12 23 415
4” 0.08 75 750
61 5” 0.04 120 1300
6” 0.04 160 1800

62. Wade-HydroMax Siphonic Products
3”, 4”, 5” and 6” Drain Accessories
Leafguards, Debris Guards, Underdeck Clamps and Bearing
Pans are available for all drains.
Our 3” and 4” Drains are
available as Podium Deck Drains
Drain shown with Debris Guard
62

63. HydroMax Siphonic Drain Benefits
• High Performance
• Versatile and Compatible with any Roof
• Compact for installation in gutters/scuppers
• Anti Tamper Fastening of one-piece Inducer
• Proven track record of Low Maintenance
63

64. HydroMax™ HDPE Siphonic System
Pre-Fabricated in Factory Controlled Conditions
with Engineered Rail Fastening System
64

65. HydroMax™ Siphonic System
60,000m² Roof
Only 4 Rainwater Downpipes draining the Main Roof
65

66. HydroMax™ Siphonic System
HydroMax™ Collector Pipe at High Level
66

67. HydroMax™ Siphonic System
Level, Small
Diameter, Pipes
Makes for Easy
Co-ordination
with structure
and services
67

68. HydroMax™ Siphonic System
HydroMax™ Pipework
Installed Absolutely
Flat Level at
High level
68

69. Development of Key Standards & Codes
• BS EN 12056-3:2000
(includes Siphonic Drain Test)
• ASME 112.6.9:2005 (Siphonic Drain Test)
• ASPE Technical Design Standard 45:2007
(Design, Installation & Product Standard)
• BS 8490:2007
(Design, Installation & Product Test Standard)

70. Development of HydroMax™
• Consultation with HR Wallingford (previously commissioned
by UK Government to study siphonic drainage) ensured our
offering progressed the technology above competitors
systems
• HydroTechnic™ hydraulic calculations report extreme
conditions giving high accuracy
(other systems report average hydraulic conditions)
• Independently tested by Hydraulic Research Centre
Wallingford (HRW) for compliance with BS EN 12056-3:2000
• Independently tested to ASME 112.6.9 (IAPMO File #5305)
• Full Compliance with current SS525, BS 8490:2007 & ASPE 45
• 100% Success Rate

71. Development of HydroMax™
• Full Compliance with SS525:2006
• Full Compliance with BS 8490:2007
• Full Compliance with ASPE Design & Engineering Standard 45
• 100% Success Rate

72. Primary and Overflow Systems
Using HydroMax Overflow System can offer the same technical and commercial
benefits obtained using the HydroMax™ Primary Drains
• Primary Roof Drains installed at roof level or at
gutter sole level
• Drains direct to underground drainage
• Overflow Roof Drain Inlet raised
Raised Inlet to Drain
to 50mm above gutter sole.
• Drains to Atmosphere often at
50mm high level or to walkways or car
parks
• Must not connect to Primary
System
(as this would normally be a vent)
72

73. Maintenance by Design
Primary Drain Overflow Drain
Raised Inducer
Level
Roof Level
Regional Options:
Dry Season Covers for Gulf Region
73

74. Siphonic Drainage Analytical Design Program
HydroMax™ provides the following:
• Web based HydroTechnic™ program for easy Technical Support
• Fast Accurate Calculations in full compliance with
SS525, BS 8490 & ASPE 45
• Advanced Edit Functions to accommodate on-site changes
• Program Generation of Pre-Fabrication Drawings
(Eliminates risk of human interface errors)
• Exports data in electronic format for O & M files
74

75. Siphonic Drainage Analytical Design Program
Metric Version
Following calculation ofUSA Version ft/in and GPM
rainfall inflows and determination of required pipe routing,
the Design Engineer ‘Draws’ the piping system into the calculation program

76. Pipe diameters are
edited to find the
USA Version
optimum solution
76
Metric Version

77. Key Advantages with HydroMax™
• Drains independently tested to:
– BS 8490:2007
– ASME 112.6.9:2005
• Designs to BS 8490 or ASPE 45
• Independently tested HydroTechnic™ design software
(confirmed to have “unsurpassed accuracy”)
• Range of High Performance Roof Drains (Outlets)
• HDPE Pipes to EN 1519 (not for North American Market)
77

78. Key Advantages for Building Owners
• High Performance, Self-Cleansing Roof Drainage System
• Fewer Rainwater Downpipes routed to convenient positions
providing an increased and flexible use of floor space
• Proven Record of Low Maintenance
• Elimination of underground drainage, manholes, etc. within
the building footprint
78

79. Key Advantages for the Design Team
• Smaller diameter horizontal pipework installed level
• An Engineered Solution allowing choice of discharge locations
• Flexible Pipe routing with easy co-ordination of services
• Rainwater Management - HydroMax™ can route pipework to
attenuation/rainwater harvesting.
79

80. Key Advantages for the Main Contractor
• Improved Construction Build Program
• Significant Cost Savings
• A dry building envelope is attained at an early stage of
construction allowing fit-out works to proceed earlier
• Less Trench work for below ground drainage saving
excavation, soil treatment, pipe laying, back fill
compaction, etc.
80

81. Engineers Training Day – Topics Covered
• Key Aspects of BS 8490:2007/ASPE 45/SS 525
• Hydraulic Parameters
• Piping Layout Design (do’s and don'ts)
• Hands-on HydroTechnic training
• Understanding how to Edit Systems within
HydroTechnic™ to cater for design or onsite changes
• Specification Writing
81

82. Information Requirements For HydroMax
to Provide Concept Designs
• Design Rainfall Rate
• Roof Plan Drawings (AutoCAD)
• Floor Plan Drawings (AutoCAD)
• Sections/Elevation Drawings (AutoCAD)
• Underground drainage Connections
• Attenuation or Rainwater Harvesting Requirements
• Gutter Profile (to allow compatibility checks)
• Specification (we can provide CSI or R10 type spec.)
82

83. HydroMax™ Siphonic Drainage
Leaders in Siphonic Drainage
www.hydromax.com