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Synopsis

A typical overview of the lifecycle stages of physical assets is shown by the diagram below – this is a sub-set of the practical i-PAM integrated asset management model, is not meant to replace any PMBOK or established Programme Management approach:

syn01

We assume (with very few exceptions) that the transition from for example “Design and manufacture” to “Install and commission…” and “Deliver service / operate assets” is smooth and simple, and involves the sign-off of the final designs, and subsequently accepting the responsibility for custody and care. But in real life the phase of installation and commissioning is only the start of a steep learning curve, mostly fully driven by anecdotal information on the reliability behaviour.

A very strong point can be made that with a little more structuring of design documentation and data, good operating and maintenance practices can be given a kick-start.

This article does not investigate the topic in detail, but merely tries to illustrate some practical considerations.

Background

As a living organism develops towards full maturity, new cells are formed. The DNA in the base cell is replicated, because it contains the blueprint of the fully developed organism. The genetic code contained in the DNA is precise – without this precision, we would probably see very unusual creatures around us.

The asset designer applies small building blocks of knowledge from the areas of mechanics, material properties, chemistry, electricity and more to create a model of the machine or plant. The clarity and level of detail contained in this model is required to be sufficient to allow the manufacturer to build the physical machine or plant; such that the functional intent is met.

Obviously, we as maintainers need to maintain the genetic code as handed over to us. This is more often than not where we start to struggle. The genetic code as developed during the design stage is often not passed on to us in a fully re-usable format; or we often don’t see the need to analyse and re-package the genetic code in order to keep the asset true to the original genetic blueprint.

Asset DNA and asset life

The design engineer forms a mental picture of the asset to be designed. The required characteristics of the asset, in particular the function and associated performance standards are supplied by design specifications and regulatory requirements. This is where the lifecycle management challenge starts – the designer will create a design which fulfils the functional requirements, and meets the associated performance standards. BUT the asset manager is not only concerned about the now and here – he fully understands that his challenge is to ensure on-going output and meeting output standards over a period of many years.

The designer is bound to meet the required characteristics of the asset in such a way that the design will

  • cost the least to construct,
  • take the shortest time to construct,
  • utilise the least amount of materials,
  • require the least input of energy,
  • and require the lowest level of scarce and expensive skills and technology to construct.

At this stage of the asset lifecycle, the client is typically interested in exactly the same cost and time considerations as the designer. The smaller the capital lay-out for the specified functionality and performance standards, the bigger the return on the investment. But is this assumption true? Only if the design capacity can be maintained, and the operating cost allows the yielding of a healthy, predictable profit over a future period.

The challenge we face as maintainers is that the asset DNA blueprint changes hands from the designer to us. More often than not the DNA blueprint we receive is made up of genetic code we cannot directly apply to the maintenance situation. The genetic code as created by the designer was precise enough to construct an asset which exactly meets the design specification, but during the hand-over from project to operations a significant portion of the genetic code becomes illegible, gets lost, or becomes obscured in a mass of un-indexed data.

The conceptual diagram below illustrates the limited transfer of the asset genetic code from design phase to operation and maintenance phase:

syn02

The requirement of the asset manager and maintainer is therefore that the DNA blueprint is carried forward into the future, in such a manner that the maintainer can faithfully ensure that the asset keeps meeting its design intent.

Conflicting interests

Current-day thinking on asset lifecycle management often uses as departure point the balancing of cost, risk, and service delivery / output. This is in itself an incongruity when only considering the now and here – a conscious increase in asset-related spending could reduce risk of various classes, increase service delivery / output; but subtracts from profit. How-ever, such increase in asset-related spending could be the only way to ensure longer-term sustainability.

There is money to be made from maintenance – especially if the operator / maintainer of the asset is fully reliant on the constructor / original manufacturer. The original manufacturer (or its agent) requires maximising profit; while at the same time the maintainer requires to minimise cost. Restricting access to the DNA blueprint of the asset is a sure-fire way to ensure that the operator / maintainer stays dependant on the original manufacturer. A simple but very realistic example of this dependency is illustrated by the example below:

The original manufacturer specifies the following (reference data) in its parts catalogue:

  • Bearing, Drum drive end, 23-789.A1

An alternative specification could be:

  • Bearing, Tapered Roller, 75x130x37, S2

If the item is bought from the OEM, the purchase price is R 2 250.00. Using the alternative specification, the item can be bought from a local bearing company for R 1 400.00, and with some shopping around, for less than R 500.00.

The example above should be read with a little caution – if the genetic code was not fully specified by the designer, the buyer might oversee the need to specify the original hardness and radial clearance as intended by the designer and buy the cheapest part; resulting in a bearing life as low as possibly 1 000 operating hours rather than the originally planned 22 000 operating hours.

A sound specification is something like:

  • BEARING, ROLLER: MANUFACTURER: MCBEARING, PART NO: 123456; TYPE: TAPER; ROW: SINGLE; INSIDE DIAMETER: 75 MM; OUTSIDE DIAMETER: 130 MM; WIDTH: 37 MM; PRECISION: HIGH; HEAT TREATMENT: S2; USED ON: LIGHTNIN 117095

So the lesson here is that it is in our best interest as asset managers to be absolutely confident that we have the correct and full genetic code for the assets.

The maintainer’s interest

The reference to radial clearance in the preceding paragraph opens up yet another dimension of the asset blueprint, namely usage- or time-induced variations from the intended asset characteristics as documented by the designer. Let us look at an example for illustrative purposes:

The bearing operating clearance as desired by the designer is 20 microns. The bearing manufacturer’s catalogue indicates that with the proper lubrication, sound operating practices, normal running conditions, and the operating temperature never exceeding 120 ˚C, the bearing should operate for 22 000 hours.

But what signifies the end of the bearing life? There is of course no single, generic answer to this question. In fact, the answer is completely empirical; unless

  1. the designer has an in-depth understanding of bearing engineering and has access to current bearing life modelling tools,
  2. the operating context remains “normal” for the full life of the bearing.

We as maintainers could therefore be in a position to insist that the designer adds a few “nucleobases to the DNA”, as in the example below:

syn03

It is clear that only a few data items additional to the original design documentation will enable the reliability engineer to develop sound going-in-position maintenance plans; which is a huge step forward from the more common “we will learn from the failures” approach which is practiced.

Conclusions

We have only scratched the surface of documenting, understanding and using the asset DNA. In particular aspects like a standard taxonomy, including basic numbering and classifying, require international standardisation. The ISO 8000 series of standards holds a lot of promise, but we as maintainers must get our requirements documented and speak with a single voice.

References:

FAG Bearing Catalogue, Standard Programme 41 500/2 EA

www.fag.de/content.fag.de/en/products_services/products_services.jsp; accessed April 10, 2015

NASA Systems Engineering Handbook, Stephen J. Kapurch

Physical Assets Management Concepts, Jan A Myburg; Article dated 14 Oct 2008.