There are many things to consider when selecting the best gas detector, and cost is not the least of them. But how many of you consider total cost of ownership?
Once the desired specification has been determined, there are likely to be a number of detectors, available over a range of purchase prices, that come close enough to meeting that spec to be considered. But the purchase price is not the only cost associated with owning a gas detector. There are also on-going costs of maintenance, which can be significant over the life-time of a unit.
So, other than purchase price, what kinds of things should be considered when thinking about cost of ownership?
An obvious factor is the warranty period under which relevant servicing and repair is conducted. Compared to a two-year warranty, a three-year warranty provides a year of saving on cost of servicing and any replacement parts. This alone may make up for the difference in the purchase price between units with a two- or a three-year warranty.
Choice of technology of components can also affect the maintenance cost dramatically. For instance, if monitoring for flammable gases, pellistor-based sensors and infrared (IR) sensors may be reasonable alternative technologies. However, while pellistors are less expensive to buy, their effective lifetime tends to be significantly shorter, resulting in higher maintenance costs. Another good example is the 3-year oxygen sensor. The lower initial cost of the 2 year sensor is outweighed by the 3 year sensor when replacement costs are factored in. In both instances, if not still covered by warranty, you will be hit by the cost of the sensor and associated service costs.
Other clever design features can also save money over the lifetime of a detector. For example, if the case of a detector is damaged, this is unlikely to be covered by warranty. Depending on how easy the cover is to replace, it may not be cost-effective to consider, resulting in a need for a completely new detector. Some detectors are now being designed to make cover replacement easy, so it can be a sensible and cost-effective option.
When it comes to making the final choice on gas detectors, the best solution will be site-specific, as many local factors will feed into how much influence these and other various factors have on the lifetime cost. In these times when managers are expected to keep tight control of budgets, cost of ownership is something you might want to consider.