Altair Equivalent Filters: The Complete EPC Buyer's Guide

What Are Altair Equivalent Filters?

Altair equivalent filters are replacement filtration elements designed to interface with air intake systems originally configured around Parker Altair filtration equipment.

The term equivalent is important.

An equivalent filter should not be selected solely because it physically fits the holding frame. The engineering comparison should consider the characteristics that influence intake-system performance.

For a gas turbine intake, these can include:

• Filter dimensions and depth

• Airflow requirement

• Face velocity

• Initial pressure drop

• Filtration efficiency

• Dust-holding characteristics

• Media construction

• Frame construction

• Gasket and sealing arrangement

• Airflow direction

• Moisture and salt exposure

• Installation configuration

Parker's Altair System2 documentation, for example, describes different high-efficiency filter options with different efficiency and pressure-loss characteristics, demonstrating why filtration selection needs to consider more than physical fit.

For EPC procurement, this means an OEM-equivalent filter should be evaluated as an engineered replacement, not simply an interchangeable commodity.

OEM, OEM-Equivalent and Aftermarket Filters: What's the Difference?

The terminology used during procurement can create confusion.

An OEM filter is supplied by the original equipment manufacturer or under the original manufacturer's product system.

An OEM-equivalent filter is manufactured as an alternative to the original component and is intended to meet the relevant dimensional, functional and performance requirements.

An aftermarket filter is a broader term covering replacement products from manufacturers other than the original supplier. Not every aftermarket filter is necessarily an engineered equivalent.

The important question is therefore not simply “Is it OEM?”

It is:

“Does the replacement satisfy the technical requirements of the installed intake system?”

That question should drive the EPC specification.

Why Part-Number Matching Alone Is Not Enough

Part numbers are valuable starting points, but they do not provide the complete engineering specification.

A replacement filter can share a nominal size with the original and still have a different:

• Media construction

• Efficiency

• Pressure-drop characteristic

• Filter area

• Pocket configuration

• Frame material

• Gasket position

• Sealing method

• Moisture resistance

• Dust-loading behaviour

This is particularly important where a filter is part of a multi-stage gas turbine intake system.

Parker's Altair System2 range includes different high-efficiency filter configurations, with published performance differences between options such as HVL, HVX and HVY. The manufacturer's documentation identifies different pressure-loss and small-particle-efficiency characteristics for these configurations.

Consequently, EPC engineers should use the existing part number to identify the starting configuration, then verify the complete replacement specification.

What Should an EPC Specification Include?

A good filter specification should contain enough information for a supplier to identify the correct replacement without relying on assumptions.

Dimensional information

Record:

• Face dimensions

• Filter depth

• Pocket depth where applicable

• Frame dimensions

• Gasket location

• Holding-frame interface

• Installation orientation

Performance information

Where available, specify:

• Design airflow

• Face velocity

• Initial pressure drop

• Maximum allowable pressure drop

• Filtration efficiency

• Test method

• Dust-loading requirements

• Operating temperature

Construction information

Also establish:

• Media type

• Frame material

• Support construction

• Adhesive or bonding arrangement

• Gasket material

• Seal configuration

• Drainage requirements

This information allows an EPC team to compare alternatives on engineering characteristics rather than price alone.

Altair System 2 Filters

Altair System 2 is a high-velocity gas turbine intake filtration platform designed for demanding environments, including offshore and coastal installations.

Parker's documentation identifies a cleanable PBR pre-filter and three disposable high-efficiency bag-filter options within the System2 range. The system is designed around high airflow, dust-holding capacity, salt removal and pressure-loss considerations.

For an EPC replacement, engineers should establish which stage is being replaced.

Pre-filtration

The pre-filter is intended to remove larger contaminants and reduce the loading placed on downstream high-efficiency filtration.

Airguard's PBR-AG, for example, is specified as an OEM-equivalent pre-pocket filter for Altair System 2, Neptune and Vega applications. Its published specification identifies high-velocity mechanical pre-filtration and an offshore/coastal/marine application range.

High-efficiency filtration

The final or high-efficiency stage requires a different assessment.

Engineers should compare:

• Required efficiency

• Airflow

• Initial resistance

• Loaded resistance where applicable

• Filter area

• Media construction

• Salt and aerosol performance

• Holding-frame configuration

For an EPC project, these parameters should be included in the technical submittal rather than relying solely on an “Altair equivalent” description.

Altair Neptune Filters

Altair Neptune installations can require similar attention to staged filtration, particularly where the intake system operates in coastal, marine or contaminated environments.

Airguard currently identifies several OEM-equivalent products as compatible with Altair System 2, Altair Neptune and Altair Vega, including pre-filters, coalescer panels and high-efficiency pocket filters.

This illustrates an important procurement principle:

Compatibility with the system family does not eliminate the need to select the correct filtration stage.

A pre-filter, coalescer and high-efficiency pocket filter perform different functions.

For example, Airguard's CP2-AG is an OEM-equivalent coalescer panel filter for Altair System 2, Neptune and Vega systems. Its stated technology combines coalescing and mechanical filtration and is intended for applications including offshore, marine and land-based installations.

For Neptune replacement projects, EPC teams should therefore identify:

• The existing filtration stage

• The holding-frame dimensions

• Design airflow

• Environmental exposure

• Required filtration performance

• Pressure-drop limits

• Drainage and sealing requirements

Altair Vega Filters

The Altair Vega filtration system also requires application-specific evaluation because configurations can vary according to the required intake protection.

Parker documentation describes Vega configurations involving vane separation and filter coalescing, including arrangements designed to handle airborne water, sea spray and fine droplets. It also identifies different configurations for gas turbine, diesel-engine and HVAC applications.

This matters when specifying an equivalent because the filter cannot be evaluated independently of the air-intake architecture.

For wet or marine environments, engineers may need to consider:

• Bulk water removal

• Fine aerosol capture

• Drainage

• Salt aerosol exposure

• Air velocity

• Pressure loss

• Downstream filter protection

Airguard's current product range includes several equivalent filters identified for Altair Vega applications, including PFA-AG, CP2-AG, PC2-AG, PBR-AG and high-efficiency pocket-filter options.

Altair Aquila Filters

Altair Aquila should be treated as a separate system reference during EPC specification rather than assuming that every System 2, Neptune or Vega filter is automatically interchangeable.

Airguard currently identifies its Altair/Parker-compatible gas turbine filtration range as covering System 2, Vega, Neptune and Aquila.

However, the engineering process remains the same:

Identify the installed configuration → establish the filter specification → verify physical compatibility → confirm performance requirements → review environmental conditions.

For an Aquila project, the EPC specification should therefore include the existing filter reference, dimensions, system configuration and available technical documentation before an equivalent is approved.

Filter Staging: Pre-Filters, Coalescers and High-Efficiency Filters

A major mistake in replacement procurement is treating every filter in the intake system as performing the same job.

A staged filtration system may use different elements to manage different contaminant types.

The correct replacement therefore depends on where the filter sits within the intake system.

Airguard's current Altair-compatible range includes pre-filters, coalescer panels and high-efficiency pocket filters rather than treating all replacement requirements as a single filter type.

Pressure Drop: The EPC Parameter That Should Not Be Ignored

Pressure drop is one of the most important parameters when comparing equivalent gas turbine intake filters.

A filter creates resistance to airflow.

As the filter loads with particulates, resistance can increase further.

For EPC design, this means the filter must be considered within the available fan or turbine intake pressure envelope.

A higher-efficiency filter is not automatically the better selection if its resistance is incompatible with the system design.

The comparison should include:

Parker's published System2 data demonstrates that different filter configurations can have different system pressure-loss and efficiency characteristics.

This is why EPC teams should request the pressure-loss curve or applicable performance data, rather than accepting a single generic pressure-drop value.

Airflow and Face Velocity

Filter face velocity is calculated from airflow divided by the effective filter face area:

Face velocity = Airflow ÷ Filter face area

As face velocity increases, the aerodynamic and filtration behaviour of the filter can change.

The filter therefore needs to be evaluated at the actual operating airflow rather than under an unrelated test condition.

Airguard's published Altair-compatible products demonstrate different airflow specifications depending on construction. For example, PFA-AG provides a pressure-loss curve across a stated 1–10 m/s range, while HV2-AG publishes airflow figures against face velocity for a 597 × 597 mm face.

For EPC documentation, always establish:

• Number of filters

• Total effective face area

• Design airflow

• Maximum airflow

• Face velocity

• Pressure drop at operating point

Offshore and Coastal Applications

An Altair-equivalent filter for a land-based installation may not be the appropriate choice for a marine or offshore application.

Coastal and offshore intake systems can experience:

• Salt aerosols

• Sea spray

• High humidity

• Fine particulate

• Wet contamination

• Corrosive environments

Parker specifically describes Altair System2 as suitable for offshore and coastal environments and identifies salt removal, dust holding and pressure-loss performance as important system characteristics.

Equivalent-filter selection should therefore consider environmental exposure alongside efficiency.

Airguard's PFA-AG, for example, is specified for offshore, coastal and marine applications and uses high-velocity mechanical pre-filtration.

For wet or aerosol-heavy applications, coalescer construction may also become important. Airguard's PC2-AG is specified for Altair System 2, Neptune and Vega systems and is designed to help protect intake systems from moisture and liquid aerosols.

Media Selection and Filter Construction

Two filters with identical external dimensions can still behave differently if their media and construction are different.

Engineers should establish:

• Media type

• Media area

• Fibre construction

• Support arrangement

• Pocket geometry

• Frame material

• Adhesive system

• Gasket arrangement

For example, Airguard's HXA-AG is specified as a high-efficiency pocket filter for Altair System 2, Neptune and Vega, using high-velocity mechanical filtration for salt aerosol and sub-micron particulate applications.

This type of product-level information is more useful for technical comparison than simply stating that a filter is an “Altair replacement.”

Sealing and Bypass Control

Even a high-efficiency filter can underperform if contaminated air bypasses the filter media.

EPC specifications should therefore address:

• Gasket position

• Gasket material

• Holding-frame interface

• Filter-to-frame seal

• Adjacent-filter sealing

• Installation orientation

• Clamping arrangement

The objective is to ensure that airflow passes through the intended filtration media rather than around it.

For high-efficiency turbine intake filtration, sealing should be considered part of the filtration system, not an installation detail to be addressed after filter selection.

How to Compare Altair Equivalent Filters

A technical comparison should use a structured matrix.

This matrix can be incorporated into EPC technical submittals and supplier comparison documents.

What EPC Buyers Should Request From a Filter Supplier

Before approving an equivalent filter, request a technical package appropriate to the project.

Recommended documentation

• Product datasheet

• Dimensional drawing

• Part-number cross-reference

• Filter efficiency information

• Pressure-drop data

• Airflow range

• Media description

• Frame specification

• Gasket/sealing details

• Operating temperature

• Application limitations

• Relevant test documentation

• Manufacturer and manufacturing location

• Warranty information where applicable

Not every project will require every document.

The required documentation should reflect the criticality of the application and the EPC project's specification.

Airguard Altair-Equivalent Filter Range

Airguard Envirocare manufactures OEM-equivalent filtration products in Wolverhampton, UK, and its current range includes products identified for Altair/Parker intake systems across System 2, Neptune, Vega and Aquila applications.

Examples of currently listed Altair-compatible products include:

These are examples rather than a universal substitution list. Final selection should be based on the installed system, filter stage, dimensions, airflow, performance requirements and environmental conditions.

EPC Procurement Checklist for Altair Equivalent Filters

Before issuing a purchase order, confirm:

System identification

• Altair/Parker system identified

• System configuration recorded

• Existing filter part number recorded

• Filter stage identified

Dimensional verification

• Width confirmed

• Height confirmed

• Depth confirmed

• Holding-frame interface confirmed

• Gasket arrangement confirmed

Performance verification

• Design airflow confirmed

• Face velocity calculated

• Efficiency requirement established

• Initial pressure drop reviewed

• Allowable pressure drop confirmed

• Relevant test data reviewed

Environmental verification

• Dust loading assessed

• Salt exposure assessed

• Moisture/aerosol exposure assessed

• Temperature range confirmed

• Offshore/coastal requirements identified

  Procurement verification

• Manufacturer identified

• Equivalent part reference documented

• Technical submittal approved

• Documentation retained

• Repeat-order reference established

This process gives EPC teams a repeatable method for qualifying replacement filtration rather than treating every order as a standalone purchase.

Common Mistakes When Buying Altair Equivalent Filters

1. Matching only the dimensions

A filter can fit physically while having unsuitable pressure-drop or efficiency characteristics.

2. Treating all Altair systems as identical

System 2, Neptune, Vega and Aquila should be identified separately during specification.

3. Ignoring filtration stage

A pre-filter is not interchangeable with a high-efficiency pocket filter simply because the external dimensions are similar.

4. Comparing efficiency without pressure drop

Higher efficiency can involve different resistance characteristics. Both parameters should be evaluated.

5. Ignoring environmental conditions

Marine, coastal and offshore installations can impose requirements that differ significantly from dry onshore applications.

6. Treating part numbers as complete specifications

The part number should be the starting point for technical verification, not the end of it.

7. Approving without documentation

EPC projects need a traceable technical record for the selected replacement.

Key Points for EPC Procurement

• Altair equivalent filters should be technically qualified, not selected by name alone.

• Physical dimensions are only one part of filter equivalence.

• Airflow, face velocity and pressure drop should be evaluated together.

• Filtration stage must be established before selecting the replacement.

• System 2, Neptune, Vega and Aquila should be treated as distinct system references.

• Offshore and coastal applications require additional consideration of salt, moisture and aerosols.

• Part-number cross-reference should be supported by dimensional and performance verification.

• Filter sealing is part of effective system performance.

• Technical submittals should contain enough information for engineering approval.

• A repeatable specification reduces procurement risk on future replacement orders.

FAQs

1. What is an Altair equivalent filter?

An Altair equivalent filter is a replacement filtration product designed to meet the relevant physical, functional and performance requirements of an Altair/Parker intake application. Equivalence should be verified against the actual system specification.

2. Are Altair equivalent filters the same as OEM filters?

No. An OEM-equivalent filter is an alternative manufactured to meet applicable requirements. It should be technically evaluated against the original filter and intake-system requirements before approval.

3. Can I replace an Altair filter by matching the part number?

The part number is useful for identification, but it should not be the only verification method. Dimensions, media, efficiency, airflow, pressure drop, sealing and application conditions should also be checked.

4. What information should an EPC contractor provide when requesting an equivalent filter?

Provide the original part number, dimensions, filter stage, airflow, efficiency requirement, pressure-drop information, equipment/system reference and operating environment wherever available.

5. Do Altair System 2 and Neptune filters use the same replacements?

Some Airguard products are listed as compatible with both systems, but compatibility is product-specific. The exact filter stage, dimensions and performance requirements should still be verified before substitution.

6. Why is pressure drop important when selecting an equivalent filter?

Pressure drop represents resistance to airflow. A replacement with unsuitable resistance can affect the intake system's operating conditions, so the proposed filter should be evaluated at the relevant airflow and face velocity.

7. Are Altair equivalent filters suitable for offshore applications?

Some are specifically designed or listed for offshore, coastal and marine applications. The selection should account for salt aerosols, moisture, dust loading, airflow and the required filtration stage.

Conclusion

Selecting Altair equivalent filters for an EPC project requires more than finding a replacement with a similar part number or external dimensions.

The technically sound approach is to establish the complete requirement: system configuration, filtration stage, dimensions, airflow, face velocity, efficiency, pressure drop, media, sealing and operating environment.

For System 2, Neptune, Vega and Aquila projects, this information provides the basis for comparing OEM-equivalent alternatives and preparing a defensible technical submittal.

Airguard Envirocare manufactures OEM-equivalent gas turbine intake filters in the UK and supplies filtration solutions for demanding power-generation, oil & gas, marine and industrial applications. Its current Altair/Parker-compatible range includes pre-filters, coalescers and high-efficiency pocket filters.

For an EPC quotation or replacement assessment, provide the existing filter part number, dimensions, airflow and application details so the proposed equivalent can be evaluated against the actual installation rather than selected from a generic cross-reference.