When specifying a filtration system, many projects focus heavily on capital expenditure and obtaining the lowest possible purchase price. Whilst the upfront cost of a filtration housing is important, it often represents only a small proportion of the total cost over the lifetime of the installation.
Industrial filtration systems commonly remain in service for 10–20 years. During this period, operating costs such as replacement filter cartridges, maintenance labour, downtime, inventory holding and energy consumption can significantly exceed the original equipment cost.
Incorrectly sized filtration systems can lead to one of two poor operational situations. In both cases, the result is a higher total cost of ownership for the end user.
A correctly sized filtration system should provide:
When systems are oversized or undersized, these benefits are often lost, leading to increased expenditure and reduced process efficiency.
Less commonly considered is the issue of oversized filtration systems.
Naturally, there is the additional cost of the initial installation, where the end user pays more for the filtration housing and the initial fill of cartridge filters.
This significantly increases the upfront investment, particularly where the housing has expanded in diameter rather than height. An industrial housing that doubles in size – for example from a 10-cartridge housing to a 19-cartridge housing – may result in costs that are 1.6 to 1.8 times greater. When dealing with higher specification hygienic or sanitary housings, the increase can be even greater.
Whilst an oversized filtration system will generally provide longer cartridge life due to a lower clean pressure drop and greater filtration area, this benefit is often lost if the operator changes cartridges based on a fixed maintenance schedule rather than actual cartridge condition.
In these situations, cartridges are frequently removed before they have reached the end of their useful life.
There are also hidden costs to consider, including:
In many facilities, these hidden costs go unnoticed because they are spread across multiple departments.
Your filtration system may be oversized if:
This is one reason why end users should always insist on differential pressure monitoring being fitted to the filtration system.
By measuring pressure before and after the filter housing, operators can accurately determine cartridge condition and maximise usable filter life.
Undersized filtration systems are considerably more common.
This typically occurs when a contractor or end user focuses solely on minimising the initial capital cost of the installation. By extension, some suppliers focus on providing the smallest possible housing without fully explaining the long-term impact on operating costs.
A smaller housing contains less filtration area, meaning each cartridge must process a greater proportion of the flow and contaminant load.
As a result:
If, for example, a housing is only half the size required, it may consume between three and four times the number of filter cartridges compared to a correctly sized filtration system.
Any savings achieved on the initial housing purchase are quickly lost through increased consumable expenditure.
For filtration systems operating over a 10–20 year period, these additional operating costs can be substantial.
Common indicators include:
These symptoms often indicate that the filtration area available is insufficient for the process requirements.
To illustrate the impact of filtration system sizing, consider the following simplified example.
Assuming a cartridge cost of £40 each:
Correctly Sized System
Undersized System
Over a 15-year operating life:
Correctly Sized System
Undersized System
This represents an additional £27,000 in cartridge costs alone, before labour, downtime and maintenance costs are considered.
Whenever a new filtration system is specified, the design clean pressure drop should be known.
Not only does this provide an effective method of comparing filtration systems from different manufacturers, but it also gives the end user a benchmark for measuring performance during commissioning and operation.
Differential pressure monitoring is often the most reliable way of determining when a filter cartridge has reached the end of its useful life.
Without pressure monitoring:
With pressure monitoring:
For many facilities, pressure gauges are a relatively small investment that can deliver significant long-term savings.
Another factor frequently overlooked is energy consumption.
Undersized filtration systems typically operate with higher clean pressure drops, forcing pumps and process equipment to work harder to maintain required flow rates.
This can result in:
Whilst cartridge costs are often closely monitored, energy costs associated with excessive pressure losses can accumulate significantly over the lifetime of a filtration system.
Frequent filter changes can interrupt production runs, increase labour costs and reduce operational efficiency.
Incorrectly sized systems can lead to unstable flow rates, excessive cartridge consumption and unnecessary operating expenditure.
Frequent maintenance interventions increase operating costs and expose personnel to additional handling requirements.
Poor filtration system sizing can increase validation complexity, reduce process consistency and drive up consumable costs.
The lowest-cost filtration housing is not always the lowest-cost filtration solution.
Whether a system is oversized or undersized, the result is often increased operating costs, unnecessary maintenance and reduced process efficiency.
Understanding clean pressure drop, cartridge loading, filtration area and differential pressure monitoring at the design stage can significantly reduce total cost of ownership over the lifetime of an installation.
If you are reviewing an existing filtration system or specifying a new one, PoreFiltration can help assess whether your current design is optimised for both performance and long-term operating costs.
We source cost-effective, reputable and readily available filtration products across Food & Beverage, Chemicals & Solvents, Medical and Process Water applications.
If you'd like a no-obligation quote or advice on how you could cut your filtration costs, then give us a call or send us an email, we'd be happy to help
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