DESIGN : DEAR PLUMBERS 25
Quality assurance is a process
By
D . S ( Vollie ) Brink Pr . Eng . MSAICE , MPMISA
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 .
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 .
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 were 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 was 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 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 .
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
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 wellearned retirement .
“ I have found that the more detailed information you give the contractor , the better quality you can expect . ”
June 2023 Volume 29 I Number 4 www . plumbingafrica . co . za