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Sanitary and Rainwater Drainage Design: BS EN 12056

Upcoming Courses 
Key Areas  
Course Content
Learning Outcomes
Who Should Attend
Course Timings
Course Fees
In-House Training

A full overview and agenda, need to know information and booking instructions can be found on the individual course pages. Click on a course code below to view. 

Upcoming Courses

5th April 2019 | London - Book Here

Key Areas 

  • An overview of previous Standards
  • Explanation of terminology within BS 12056, and comparisons with the Approved Document H
  • Sanitary design criteria
  • Sanitary design flow calculations and pipe sizing
  • Calculation of rainwater catchment areas and design flows
  • Eaves gutter sizing, rainwater pipe sizing and flat roof drainage calculations
  • Use of weir flow calculations

Course Content

This course will cover the application of BS EN 12056 for the design of above ground gravity drainage systems, including reference to Approved Document H. Example calculations to solve realistic design scenarios will also be included.

Session 1- Introductions

  • History of drainage design and standardisation

  • BS EN12056 Gravity drainage systems inside buildings – structure, concepts and terminology. EN 12056 – 1 (General and performance requirements)

  • Stack pressure profile, stack flow cross-section, offsets

  • The different Systems, square and swept entries, filling degrees, capacities

  • Alternative approaches to drainage eg Sovent, Vacuum, rifling,

  • Discharge units and other design systems

Session 2 EN 12056-2 Sanitary pipework, layout and calculation

  • Calculation examples for a bathroom and kitchen

  • Calculations for a house, a flat, a block of flats etc

  • Selection of pipe size and ventilation options

Session 3 EN 12056-3 Roof drainage, layout and calculation

  • Rainfall in the UK, climate change

  • Stormwater and flooding issues

  • Hierarchy of disposal, SuDS, driveways

  • Limitations of EN 12056-3, balconies, syphonic systems, drainage chains, French drains

  • Gutters, parapets, overflows and off-sets

  • Simple calculations for ‘normal’ rainfall on a house

  • Calculations on 100 year storms and other ‘infrequent’ events.

  • Combined and separate drainage systems

Session 4 - The other parts of EN 12056 and legislation 

  • Problems with rainwater systems in real buildings

  • EN 12056 – 4 (Wastewater lifting plants. Layout and calculation),

  • EN 12056 -5 (Installation and testing, instructions for operation, maintenance and use)

  • UK Building Regulations and other relevant legislation

  • Quiz and questions

Learning Outcomes

  • Explain the background of sanitary Standards
  • Describe the format and application of the UK Regulations
  • Describe the format of BS EN 12056
  • Explain the terminology and classifications used within BS 12056
  • Differentiate between BS EN 12056 and the Approved Document H
  • Size sanitary stacks and branch pipes
  • Calculate the rainwater flow rate from catchment areas  
  • Size eaves gutters and rainwater pipes
  • Determine the drainage requirements for flat roofs
  • Use weir flow calculations

Who Should Attend 

This course is designed for people with limited knowledge of above ground drainage systems who would like to be more confident in their design, and will therefore be principally suited to new entrants into the field of public health engineering and mechanical engineers wishing to broaden their knowledge.

Course Timings 

Registration will be at 09.30
Start Time: 10.00
Latest Finish: 5.00

Course Fees 

  • Members Rate: £336 (£280 ex VAT)
  • Standard Rate: £372 (£310 ex VAT)

In-house training at your site

Training multiple staff at once is the most cost effective way to develop staff for organisations. All our courses can be delivered at your site (min 6 staff) at discounted rates. These In-House courses are only available in the UK and Europe. For an In-house quote please email; 
Name of course, approximate number of staff and your site address 


To contact the CIBSE Training Team with a query please

Email: or call: +44 (0)20 8772 3660