DESIGN: DEAR MR PLUMBER
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the foul contaminated air escapes into the
kitchen contaminating the entire kitchen.
A shower that is provided with this type
of floor drain have the same problem and
should not be used in a hospital.
The proposed new system
This proposed ‘nameless’ sanitary drainage
system consisting of various elements can be
configured to be used in any type of building
from a simple house to a multi-storey building,
provided the designer has a basic knowledge of
the hydraulic principles of water and soil water,
and can apply a number of basic principles as
explained above.
The proposed new system must consist of the
following elements:
For a multi-storey building:
1. Stack pipe(s)
2. Branch pipes for wastewater
3. Branch pipes for soil-water
4. Ventilation pipes
5. Back ventilation
6. Trap ventilation
7. Horizontal collector piping
8. Horizontal discharge piping
9. Vertical drop piping
10. Drain piping from the building to the
external drain (the external drain connects
the building to the sewer connection)
11. Other types of piping and elements
Buildings on ground level such as housing
1. Make a list of all the usual elements.
2. The designer must then build a complete
drainage system from these elements
to suit the usage and the required
performance in compliance with the
performance regulations.
3. If it is to be a dual system, which must
have separate piping for wastewater and
soil- water or even greywater, then it is
configured as such with the elements,
but in compliance with the performance
regulations. It becomes a design as a ‘fitfor-purpose’
and a ‘hydraulic’ design.
There are no specific drainage regulations for the
design and construction of sanitary drainage for
hospitals and perhaps this must be the design
and construction approach for hospitals.
This proposed so-called new drainage system
is actually the same old system which we had
prior to 1977, when a drainage system was just a
drainage system with no other names.
From the list of elements as noted above one
can put the elements together to form a pipe
configuration that will suit any building and
function as per the performance regulations and
in compliance with the basic criteria of health
and safety.
The configuration is the important part of the
design and to make sure it functions hydraulically
correctly and provides for what happens inside
the piping such as in the vertical stack and when
the stack turns horizontal and where the branch
pipes connect to the stack and how to prevent
backflow or overflow and so on.
We have followed the ‘rules’ from before 1977,
but forgot how to think and have become
stagnated and cannot think out of the box.
We have developed modern equipment to solve
one problem, not realising it caused more serious
problems because we have rules for rules and
we are not allowed to deviate from these rules
and think.
We have become confused and we don’t know
the difference between a regulation and a rule.
A regulation refers to the directive or statute
enforced by law, a rule is not necessarily legal
binding, but rather, widely accepted.
With this proposed thinking (which is oldschool,
but valuable) I would like to see a new
approach to the design of sanitary drainage
systems without all the names and just design
a system by configurating all the elements into
appropriate systems that function as the specified
specification, which is the only regulation. PA
“We have become
confused and we
don’t know the
difference between
a regulation and a
rule.”
October 2020 Volume 26 I Number 08
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