Acoustics and Architecture
Hayzel
PH2DrainageTutorial.pptxBuilding Services Applications
Drainage Review
Presentation by
Chris
Puttick
Senior Lecturer Building Services
January 2020
Worked Example
In this example we will focus on working through the design using Part H of the building regulations. Considerably more detail is provided within the BS however at this level the regulations are adequate.
Worked Example
Break out group 1
Draw the pipework layout
Draw the schematic
Work out your demand units through the pipe
Convert to flow rates
Hints:
Consider the impact of ventilated and unventilated branches.
Consider where you are going to locate your vertical stacks
Assumptions:
You are dropping directly into the ground
Worked Example
Layouts
Worked Example
10 WCs
Layouts
8 WHBs
1 WC +
1 WHB
Worked Example
From Building Regulations Part H:
Considering WCs
Layouts
Worked Example
10 WCs in total.
If unvented then max of 8 allowed
Also a door in the way of the two groups of WCs, which would get in the way of the pipe!
=>
Split into 2 groups of 5
Each group drops into a vertical soil pipe
This can go anywhere behind the WCs, final location most likely dependant on what’s going on above and below. Note the hidden wall behind, this is typical
Layouts
Worked Example
From Building Regulations Part F:
Considering WHB
Layouts
Worked Example
8 WHBs in total
4 max on each run
=>
Again split into 2 groups of 5
Each group drops into a vertical soil pipe
This can go anywhere behind the WHBs, final location most likely dependant on what’s going on above and below.
Layouts
Worked Example
Another option is to take both sides into the centre
This is down to you as a designer!
Layouts
Worked Example
In both cases there is a ‘hidden wall’ behind an IPS system (where the toilet cistern can be hidden).
This also acts as a space to hide this low level waste pipework and is a normal solution for WCs.
Layouts
Worked Example
Finally the little WC.
Firstly where should the vertical waste pipe go?
Layouts
Worked Example
In the IPS on the other side of the wall would work well
Layouts
Worked Example
Which could also be used for the WHBs, so remove the extra one
Layouts
Worked Example
What if we add two more WHBs?
Too many to take into the stacks at either end….so what do we do?
Layouts
Worked Example
What if we add two more WHBs?
Too many to take into the stacks at either end (limited to 4)
….so what do we do?
Layouts
Worked Example
OPTION 1
Put in an additional stack
Layouts
Worked Example
OPTION 2
Referring back to Part H…..page 10
Layouts
Worked Example
OPTION 2
Ventilated pipework to serve 5 No WHBs
Layouts
Worked Example
Label your vertical stacks to help with referencing your schematics
Layouts
2
1
4
3
Worked Example
Break out group 2
Draw the pipework layout
Draw the schematics
Work out your demand units through the pipe
Convert to flow rates
Hints:
Consider the impact of ventilated and unventilated branches.
Consider where you are going to locate your vertical stacks
Assumptions:
You are dropping directly into the ground
Worked Example
Level 1
Level 2
Roof
Ground
Schematics
Start with your WCs and the vertical stack pipe
Show the levels the pipe goes through the building
(from the roof to the ground)
1
Worked Example
Level 1
Level 2
Roof
Ground
Schematics
Connect up the WCs
1
Worked Example
Off to the main below ground drainage system
Level 1
Level 2
Roof
Ground
Possible other connections on level 2 (not shown on this example
Schematics
Finish off the schematic
Roof Cowl, allow air in to vent but stop rain coming in
1
Worked Example
Level 1
Level 2
Roof
Ground
Schematics
3
Worked Example
Level 1
Level 2
Roof
Ground
Schematics
3
Worked Example
Level 1
Level 2
Roof
Ground
Schematics
3
AAV
It needs to be ventilated!
In this case I’m going to use an AAV
Worked Example
Level 1
Level 2
Roof
Ground
Schematics
3
AAV
The height of the AAV should be above the level of the WHB. This means if there is a blockage in the pipe you will see it come out of the WHBs not leaking out the AAVs (which may well be hidden….you’ll never know it’s blocked...until you can smell it….)
Worked Example
So we need an AAV at the end of both the runs of the WHBs, which will need access
Should show this on your layout!
Worked Example
Remember that also has the accessible WC connected to it
Schematics
3
Worked Example
Level 1
Level 2
Roof
Ground
Schematics
3
AAV
Worked Example
Level 1
Level 2
Roof
Ground
Schematics
3
AAV
These are run on separate horizontal pipes with their own connections to the SVP to reduce any back pressure impact.
Worked Example
Break out group 3
Draw the pipework layout
Draw the schematics
Work out your demand units through the pipe
Convert to flow rates
Hints:
Remember to add DUs not flow rates
Work out the overall demand unit per soil stack
Assumptions:
Assume you have the same setup on the floor above
Worked Example
Off to the main below ground drainage system
Level 1
Level 2
Roof
Ground
Schematics
Roof Cowl, allow air in to vent but stop rain coming in
1
Worked Example
Level 1
Level 2
Roof
Ground
Schematics
3
AAV
AAV
Worked Example
Demand Units and flow rate
Worked Example
Level 1
Level 2
Roof
Ground
Schematics
3
AAV
AAV
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
1.5
1.5
= 0.7 x 6.6 = 4.62 l/s
Do this for all stacks
