maintenance in gas detection: how to work efficiently and ...€¦ · the legal maintenance...

1© Drägerwerk AG & Co. KGaA

The legal maintenance requirements for gas detection equipment are strict – for a good reason. But the effort generates costs. How can the requirements be met without affecting efficiency?

Maintenance in gas detection: How to work efficiently and stay compliant.


SAVING COSTS THROUGH MORE EFFICIENT FLEET MANAGEMENT

FLEET MANAGEMENTFleet management is defined as the management, operation, and controlling of the equipment inventory. This includes:• Equipment release and return • Operational planning• Organisation and optimisation of the work flow• Requirements planning for new acquisitions • Maintenance and repair management• Procuring replacement parts and consumable

materials• Controlling• Reading and reporting measurement data

There is a lot to doOn a medium-sized oil platform, at least 1 to 50 mobile gas measurement instruments are generally in operation. There may be several hundred in a refinery or steelworks, and a medi-um-sized chemical plant may easily have a thousand or more. Each single one of these should be tested for proper function—before each use, so in general on a daily basis. Depending on the manufacturer, type of sensor, and hazardous material, a so-called bumptest takes between several seconds and two min-utes at most—not an issue for half a dozen detectors. With a larger number of instruments, or when the time capacity of the responsible staff is limited, the daily bumptest of the in-strument fleet can, however, become a logistical challenge. Its organisation is a central task of fleet management. In addition, regular calibration of all instruments, maintenance and repairs are required. The general rule applies “larger number = more time spent”. However, as the number of instruments increases, so do the opportunities for finding and implementing savings potentials through targeted analyses and more efficient control.To this end, five areas in particular should be focused on:

1. Acquisition Can you spontaneously say how many instruments on average are in operation on your plant each week and how many are kept in reserve on the shelf? How many are in maintenance and repair at the present time and how high was your need at the peak during the last outage?

Hardly anyone keeps this information in their head. But that doesn‘t matter these days, because an efficient workshop software can deliver inventory data with just a few clicks of the mouse. Unfortunately, the technical possibilities are not utilized everywhere—with the result that in practice uneconomic over-capacities are found, as well as instrument pools that are so tight that any outage or incident can endanger safety.

One of the most important tasks of fleet management is, however, to ensure that operable instruments are available at all times—in many facilities this means 24/7, so around the clock. But exactly how many are needed for this?

© Drägerwerk AG & Co. KGaA 3

As many as required, as few as possibleThe basis for the calculation must of course be the respective fa-cility-specific risk analysis. Experts recommend taking into account the following additional aspects:– Do contractors work on the plant for whom—potentially for a

limited time only—additional instrument capacity must be made available?

– How high are the failure rates of instruments in the bumptest?– What are the plant-specific maintenance intervals?– Are there any impending changes or product changes that could

affect the hazard situation?

Whether the amount suggested by these calculations is sufficient in practice must be tested in the operating plant. A fleet management software can be a big help here: It delivers valid data on the average capacity from which savings potentials can be derived. If, for ex-ample, it is found that the instrument inventory is practically never at complete capacity, a reduction of the fleet can be discussed. After all, unused instruments must also be regularly calibrated and maintained so that they can be operated at any time—a cost factor one could do well without.

How many instruments are really needed? All systems clear? And might it be possible to do without a couple of instruments? Availability analysis—here with the software Dräger X-dock manager—delivers the answer and provides indications for potential savings.

Device availability


100

75

50

25

0Pac® 5500

(quantity: 37)X-am® 5600

(33)Pac® 3500

(4)Pac® 7000

(120)X-am® 2500

(29)X-am® 5000

(51)X-am® 2000

(31)Pac® 3500

(9)

Source: Dräger Available Assig. and defect Unavailable Assigned


For maintenance work, outages, or in other situations where there is an increased need for instrumentation, rental equip-ment can often provide the desired additional equipment more cost-effectively. This approach is generally more economical than maintaining a permanent fi xed reserve that is rarely used.

During demand peaks: renting rather than purchasing?Example outage: Covering the additional need through rental equipment brings cost savings of around 15 percent— in this example corresponding to ~ EUR 2,000 to 4,000.

2. Workshop organisation In theory, a simple matter: The larger the facility, the more suitable a decentralised organisation, says economic science. Reasons include the rising overhead costs associated with administration and control tasks. In a refi nery or at a chemical plant, “size”, however, usually means fi rst and foremost long distances.

Source: Dräger

Costs in EUR

80 detectors for day to day; 40 rental devices for 3 weeks120 detectors in fl eet to also cover peak needs


25,000

20,000

15,000

10,000

5,000

0


Decentralised organisation: On-site testing saves time and effort

Decentral bumptest by users on-site

Central documentation for

safety engineers, work-shop technicians, site

manager, hygienists, …

Decentral bumptesting ensures lowest effort for bumptesting logisticsCentral documentation is key component for safety process → bumptests performed can be ensured

Local data synchronized to central database

Tests in central workshop by workshop technicians

Efficiency versus safety?In contrast, if there are several decentralised instrument storage sites or testing stations, control must be regulated in a different way. Fleet management systems record any instrument-related action and offer the equipment manager at the central site a virtual representation of his decentralised fleet: He can see how many single gas detectors are at the measuring station two kilometres away at Hydrocracker, and when the instrument needs calibration. If required, he is even notified by email—for example at Dräger X-dock—when an untested instrument is used somewhere on the plant. The measurement data from the various detectors are also collected at a central site.

The greater the distance, the larger the savings potentialSample calculation with the following assumptions: A worker who costs EUR 20/h has to walk ten minutes to a central workshop, 230 days per year. Added to this are the costs for the workshop technician—10 minutes for the test, instrument handout and return at a labour cost of EUR 40/h.

2,300 EUR Benefits with decentralized bumptesting per device and year


2,500

2,000

1,500

1,000

500

0

Source: Dräger

Source: Dräger

Testing on-site Central


3. Total cost of ownershipIf the acquisition of a new mobile gas measuring instrument is planned, the purchaser usually first filters out the models from the overall offers that satisfy the technical requirements. In a second step, attention is focused on the price. This is under-standable—however, if one wants the best instruments from an economic standpoint, it is necessary to examine the “operational expenses” in addition to the “capital expenses”.

The following factors are of particular interest:– The sensor response time: The faster the sensor response

time, the less time is required for the daily bumptest, and that in turn means lower labour costs.

– The duration for purging: The duration of a test procedure depends, among other factors, on the construction of the calibration station. How long, for example, does it take to rinse the lines?

– Test gas consumption: Especially with large fleets, the test gas is a significant cost factor, so savings in this area are clearly noticeable. The test gas consumption is affected both by the sensor response time and by the gas-flow at the station.

– Frequency of calibration: Some instruments have to be re-calibrated every six months, some significantly more often—there are significant differences in the manufacturers’ instructions, especially for single gas detectors. Estimate how much time it takes on your plant to retrieve an instrument from the field, bring it to the workshop, test it, calibrate it, and document the results. The time spent over the entire service life of a detector adds up to a significant line item.

After looking at only three or four instruments, it becomes clear that purchase prices are broadly similar within a comparable quality class. However, the differences are much greater when it comes to operational costs. Nevertheless, in the purchasing decision high importance is assigned to the acquisition cost without giving much consideration to the operational costs—which is a mistake from an economical perspective.

EUR2,500

2,000

1,500

1,000

500

0Purchasing costs


Gas consumption Test time Handling costs – on-site testing

Handling costs – Recall to workshop

Sensor and battery replacement

Acquisition and operation: What are the costs you must bear in mind?Total cost of ownership over five years using the example Dräger X-am® 2/5x00

Source: Dräger Dräger Brand X


4. Maintenance and RepairA frequently under-estimated line item of operational costs is the time spent on maintenance work and eventual repair costs. Buy cheap, pay dearly—this saying also applies to gas measuring tech-nology. Good design and high-quality workmanship can contribute to significant cost savings over the years:– Robust constructions can withstand a lot even under rough

conditions—and that increases the service life. – High tightness, against fluids and dust for example, protects the

instruments’ interior.– Instruments that allow simple and intuitive operation require

less instruction and training.

Instruments prone to malfunction create negative cost factors in several areas: in addition to the pure repair costs (labour time, replacement parts) the shipping and documentation effort by the equipment manager must be taken into account. Unproductive work-flows are a waste of money. In addition, if instruments are frequently out of service, a larger base fleet is required to prevent bottlenecks.

The heart of a gas measuring instrument is its sensor because it plays a central role in terms of the instrument’s economic efficiency. “How long does the sensor last and what does a new sensor cost?”—these questions should be clarified when new instruments are purchased. A gas detector with long-lasting sensors can save up to EUR 1,000 over the total lifetime of the instrument1.

In addition, there are ways of increasing efficiency not just in terms of the instruments themselves, but also with respect to manage-ment, maintenance and repairs. When does an instrument have to get calibrated? Which instrument needs maintenance within the next weeks? Powerful fleet management software supports the instrument manager with automated reminders during planning – in this way, shipping packages can be bundled, thus reducing the time involved. With decentralised workshop organisation, automatic error messages for failed bumptests ensure that instruments in need of repair are not left behind at field offices. The workshop manager can also respond to errors more quickly. This in turn im-proves the availability of instruments at the plant.

5. Documentation and Data Management If there is an incident at the plant, insurance companies are pri-marily interested in whether all necessary safety measures had been accurately performed in advance. Those who are unable to prove that, for example, functional gas detectors were in opera-tion at all required sites, will have a problem ...

Who is currently working where and with which instrument? Was it properly tested first? At which site in the plant were suspicious concentrations measured during the last shift? In case of emer-gency, the safety manager must be able to answer these ques-tions practically at the touch of a button—or face being fined by the regulatory authorities. For example, in 2013, companies had to pay more than three million dollars in fines for violations against the rules/provisions of communicating hazards to the United States OSHA (Occupational Safety and Health Administration).2

Documentation and data management has become a central chal-lenge in almost all industries—a very time-consuming challenge. Efficient fleet management therefore also means automating the task of reporting as far as possible, so that time and thereby labour costs can be reduced.




SOURCES:

1 Dräger’s 4 gas detector is compared with an instrument commonly found in the market. The DrägerSensors H2S and CO

last for six years; the sensor of the comparative instrument for three years. The Dräger O2-Sensor lasts six years compared

with two years in the comparative instrument; the Dräger Ex-Sensor 4 lasts for four, compared with two years. If the four

sensors of the comparative instrument need to be replaced, the cost amounts to EUR 600—800. Together with the service time

involved in shipping the instruments plus maintenance and calibration, the costs add up to EUR 1,000.

2 The Asbestos Institute: The Value of Safety, http://www.theasbestosinstitute.com/value-of-safety-infographic (04.02.2015)

IMPRINTGERMANYDräger Safety AG & Co. KGaARevalstraße 123560 Lübeck

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