Electricity + Control September 2017

Electricity

Control

SEPTEMBER 2017

hey have forced outages and stoppages.

They consistently get emergency repairs. So,

what makes today’s Maintenance paradigm

so unsuccessful at equipment risk elimination?

Why maintenance can never stop plant

and equipment failures

Every part in every machine has a degradation

curve. The length and slope of the degradation

curve depends on a component’s engineering de-

sign and how it is cared for during its lifetime.

When parts are new they provide their best

service. As a part degrades its performance drops.

Curves are monitored and tracked using appropri-

ate condition monitoring methods. The ‘P’ (Poten-

tial Failure) point is the earliest that we can detect

changed performance. This allows the remaining

service life to be predicted so the part can be re-

placed or refurbished as planned maintenance

before it is unusable at the ‘F’ (Functional Failure)

point. Breakdowns, forced stoppages, and emer-

gency work happen to equipment, despite using

the best preventive and predictive maintenance

strategies. Their parts’ degradation curves get

dramatically cut-short. A part’s degradation curve

shortens and falls as its material-of-construction is

damaged by stress. Those unintended equipment

failure events – breakdowns, emergency repairs,

forced stoppages – result from excessive stress-

es in microstructures curtailing the part’s degrada-

So,

What is Still Wrong

With Maintenance?

Mike Sondalini, LRS Consultants Global

The role of maintenance is to eliminate operating equipment risks.

Yet, organisations using Preventive and Predictive Maintenance

strategies still have equipment breakdowns.

PLANT MAINTENANCE, TEST + MEASUREMENT

A part’s chance of failure

changeswith its stresses.

Less stress slows the

degradation rate and the

part lives longer.

Higher stress lifts the

degradation rate, and the

part’s life shortens.

Take Note!