In the matter of preventive maintenance, it is extremely necessary to carry out periodic inspections by a technically competent team of consultants with the requisite manpower and NDT set- up, writes Chetan R Raikar.
God has created many creatures in this universe and all of them need periodic health check- ups and over-hauls for the betterment and longevity of their remaining life. Similarly, mankind has built many facilities and structures in this world to help people. Equally, these structures too need to be checked and over-hauled for their long life and consistent performance.
The industrial structures are different from residential / commercial structures in several ways. Firstly, the stress levels on industrial structures are substantially higher compared to that of other categories. Some of the structures like the conveyor belt supporting system, silos, chimneys, are even subjected to reversals of stresses several times a day. Such structures are subject to fatigue much sooner than others.
The next concern is that the span of industrial structures are much longer compared to their counterparts put to other types of use. Industrial structures are subjected to varying stress levels during each day, every day.
In most cases, the maintenance is considered a a cost and never a necessity. All shut-downs are designed to suit the convenience of the mechanical/ process engineers and civil maintenance is given virtually no priority. Some organisations don’t consider civil maintenance a necessity at all, and suffer mishaps like the collapse of structures and loss of manpower and production time associated with the same.
Industrial structures, particularly in the cement industry, are highly stressed structures and need periodic inspection prior to routine maintenance. It is commercially not viable for any cement plant to employ an in-house inspection team.
External consultants with a proven track record are therefore, hired to carry out inspection of structures for either preventive maintenance or specific distress assessment.
There are records of organisations having smartly invested in such preventive maintenance activities. This pays rich dividends, both tangible and intangible to all the stakeholders. Advantages Preventive maintenance inspections totally avoid any mishap / accident of civil structures.
Brings down the cost of maintenance considerably.
Helps avoid loss of production as it prevents breakdowns.
Reduces the shut-down time as most minor maintenance works are carried out even without a shut-down and in a planned manner.
Any distress observed in a civil structure is controlled at the nascent stage, thus avoiding higher costs later.
Several types of damage are observed in industrial structures, like leakage, seepage, corrosion, tilting, buckling, sagging, deflection, etc. Most of the structures are designed efficiently, reducing the factor of safety to a bare minimum to curb costs at the time of construction. Quality is always given second preference to achieve the completion target. Hence, managementis always inclined to start the production as soon as possible to get the ROI started.
Original Construction Deficiencies (OCD) is something seen often by our teams during inspections for health assessments of industrial structures. Original poor quality means early maintenance / repairs.
Inspection for health assessment needs trained manpower and several non -destructive testing (NDT) instruments. Some simple and basic types include the Schmidt rebound hammer, Ultrasonic pulse velocity and coring. Some of the advanced instruments which are almost a necessity for such inspections include radar, infra- red thermography camera, endoscope, petrography and in-situ air and water permeability apparatus like permit and autoclam.
Not many organisations invest in these expensive instruments, which need superior technical training and competence to use. Great amount of information / data can be accumulated by using these instruments, and inference from this data can save millions for the owner.
Incomplete or inadequate level of inspection proves substantially more expensive in the long run. We have been involved in collapse investigations of some structures which were certified by a structural engineer just a few days prior to the collapse. This is a clear indication that the selection process deployed to engage an inspection agency was faulty and the client paid heavily for selecting the cheapest ( and not the best ) consultant for the job.
Some of the specialised equipment proves cost- effective as they eliminate the necessity of scaffolding in many cases for the taller structures, which is a huge cost otherwise, for visual inspection and carrying out the NDT.
It is therefore, extremely necessary to carry out periodic inspections for preventive maintenance by a technically competent team of consultants with the requisite manpower & NDT set- up.
This investment of money and effort pays rich dividends of both a tangible and intangible type to all the stake- holders and proves to be a wise decision in both the short and long term.
Chetan R Raikar, Chairman & Managing Director, Structwel.
