62
DESIGN: DEAR MR PLUMBER
Quality assurance
is a process
In the 1970s and 1980s, I was working for the then largest
consulting engineering company and was responsible for the
design of municipal township sewage and water systems, as well
as for building sanitary drainage and water systems.
By Vollie Brink, Pr Eng
At some stage, this department split into two and
formed another company. I had to join the new
company, but I was soon asked to return and form
a new division due to a large contract we had
received, which was the Sasol 2 and later the Sasol
3 project. At the time, I was the only person in this
newly established division.
Vollie Brink
Vollie Brink is one of the
industry’s longest-serving
wet services engineers.
He continues to serve on
SABS committees and
has been involved in the
Green Building Council’s
Green Star rating
system. Brink continues
to consult for various
organisations while
enjoying a well-earned
retirement.
During this period, the company had been involved with
the design of many municipal drainage and water systems
and we had to provide a resident engineer on every project.
These resident engineers were mostly young engineers who,
theoretically, were extremely competent but did not have enough
practical experience and was therefore put on site for this reason,
but under the supervision of experienced senior engineers.
I became more involved with the building services component
and less with the municipal services and the supervision of
the construction and the resident engineers. The city engineer
of one of the projects called me in for a meeting, knowing that
I am no longer involved with municipal services, and politely
complained about the quality of the workmanship of the
contractors and asked whether I could intervene.
I discovered that the contractors often ignored critical
specifications and even detail design drawing details, but
also that there was a need for a formal quality control
procedure to be followed by the contractors and supervised
by the resident engineers. This was before the Internet
existed, so I basically had to devise a quality assurance
(QA) system from my own experience and the experience
of the other, older resident engineers, together with some
information I could get from technical libraries.
We then devised a home-grown QA system that consisted
of two sections: one for the contractor’s supervisor and the
other for the actual QA document. We decided that QA is not
just a list of inspections but a process, and this process has
crucial milestones.
The responsibility for the application of the QA system
is the responsibility of the contractor, and the engineer
is responsible for ensuring that the contractor applies a
QA system. The above mentioned is all critical and the
contractor must implement and apply an approved QA
system. The milestones must be clearly identified and
recorded as the work progresses.
February 2019 Volume 24 I Number 12
QA is not a final inspection or a certificate of compliance
(CoC) inspection — it is a process and the sole
responsibility of the contractor. If anybody else issues a CoC,
then that person or body could also become liable.
The reason for having a separate part for the contractor’s
supervisor / QA officer, is to assist him/her with what to
look for and to check, inspect, and test, but it must only be
used as a guide for the development of the contractor’s own
system to be approved. There are certain inspections which
the building inspector must witness and sign off, but these
must also be included in the QA system as milestones.
The first NEC project that I was involved in required a ‘works
information document’, which requires a detailed description
with specifications and in such detail that a BoQ is not
necessary; however, I prefer having the QS as part of the
professional team.
I have found that the more detailed information you give
the contractor, the better quality you can expect. The works
information document, with an example of a QA system, full
descriptions of the systems and the tests and inspections
required, complete with standard details and all information
in detail, is essential for a successful project.
Many years ago, an article appeared in Plumbing Africa
about a court case where the architect and the engineer
had both inspected and approved a new building, but the
building collapsed. The contractor blamed the architect and
the engineer, but the outcome was against the contractor.
I am not satisfied with the sequence of the inspections of
the drainage installation, simply because if the building
inspector inspects and approves the ‘open’ pipe, and the
pipe is then covered with stones in the backfilling, and
compacted, it can damage the pipe.
Please do not depend on an inspection by another body. You
are responsible as the plumber who did the work.
Please do not deviate from the design and the specifications,
as you will become liable. However, you should put your
query in writing and ask for clarification or confirmation. It is
essential that all communication is formal and in writing.
In the final instance, you are responsible for the CoC to
the engineer. PA
www.plumbingafrica.co.za