Water, Sewage & Effluent January February 2019 | Page 12

System design issues
(Part 2): Rational design
In “System design issues (Part 1)” in the November/December 2018 issue of
Water, Sewage & Effluent, we discussed the pivotal role of design and the
associated challenges of hospital sanitary drainage and potential contamination
caused by such systems. In Part 2, we look at rational design.
By Vollie Brink
T
he most important elements of
all parts of the National Building
Regulations (NBR) are health
and safety, but also economic viability.
Unfortunately, the NBR do not address
the water and sanitation services of a
hospital or clinic per se, and therefore
the latter must be designed as a rational
design by a competent engineer, or as
R158 states, an ‘experienced engineer’.
This definition, however, is not sufficient
since it does not define the level of
competence required. It therefore
lends itself to abuse by persons not
fully competent or not even classified
as a registered professional engineer,
12
and who do not possess the necessary
level of experience or expertise.
The performance of a sanitary
drainage system is specified in
SANS10400-P: P2, which forms one of
seven ‘regulations’ of SANS10400-P.
The most important elements of the
performance requirements are that
the sanitary drainage system must
not cause a nuisance, pose a health
threat, or be unsafe, and piping must
be correctly sized to convey the
effluent safely to the municipal sewage
connection.
In my view, a blocked drain that
overflows inside a building or even in a
Water Sewage & Effluent January/February 2019
public area is a ‘serious health threat’
and such situations must be mitigated
by means of correct and innovative
rational design by a competent
registered civil or mechanical engineer.
Rational design requirements
A rational design must be based on a
comprehensive risk assessment to
prevent any contamination of the sterile
environment of both the internal and
external spaces of a hospital, based on
the performance specification as per
SANS10400-P: P2, as well as annexures
A and B.
www.waterafrica.co.za