Content Overview
Author: Magnus Attefall
Client: CTT Systems
Audience: Airline decision-makers, technical professionals, and industry stakeholders
Content Type: Editorial article/thought leadership
Purpose: Explain risks, implications, and considerations related to the humidifier pad PMA
The Objective
The topic involves technical and regulatory aspects critical to decision-makers but can be difficult to fully understand.
The objective was to clearly communicate the risks and implications associated with humidifier pad PMA, enabling informed decision-making while reinforcing trust and credibility.
My Approach
I developed the article with a focus on clarity, structure, and credibility.
The content explains technical and regulatory aspects in a straightforward and accessible way, highlighting key risks and their implications. The tone is informative and balanced, ensuring that the message supports understanding without oversimplifying important details.
The article was designed to support both awareness and decision-making within the aviation industry.
Content Highlights
- Clear explanation of technical and regulatory risks
- Structured messaging for decision-making support
- Balance between detail, clarity, and credibility
- Content adapted for both technical and non-technical stakeholders
Business Impact
- Improved understanding of risks and implications
- Stronger credibility through transparent communication
- Support for informed decision-making
- Valuable content for PR, marketing, and stakeholder communication
A humidifier pad module is a subsystem in the humidification system, inserted into the OEM humidifier housing. Not all approved parts are created equal in terms of compatibility, safety, and performance in aircraft humidification systems. In this article, you will learn the importance of using original pads to maintain the highest quality and safety.
We at CTT Systems are the leading authority in this field as the sole OEM supplier of humidification systems. We have extensive application knowledge and are uniquely positioned to highlight the risks of using Parts Manufacturer Approval (PMA) humidifier pads instead of Original Equipment Manufacturer (OEM) parts.
But don´t just trust our words – read what the producer, world-leading pad manufacturer Munters, says about the importance of using the original and certified aviation GX60 pads.
Munters’ standpoint
“Given the considerable differences in material, manufacturing processes, testing, and certification, Munters strongly advises against using humidifier pads with GX30 material in the CTT Systems Humidifiers.
The GX30 pad material is not developed, produced, or tested for aviation, unlike the GX60 pad material certified for aviation used in CTT Systems Humidifiers. Ensuring that approved materials like the GX60, developed for the specific way the humidifiers wet the pad material, are used is essential for maintaining the highest air quality and safety.”
Munters
The core issue: OEM vs. PMA
CTT Systems OEM pad parts are developed specifically for the application and are 100% compatible with the system, having been meticulously tested and certified to meet the rigorous safety and performance standards established by aircraft manufacturers and aviation authorities.
In contrast, PMA parts, although tested, typically only need to meet basic environmental standards and do not undergo comprehensive functional testing for specific systems, such as those of CTT Systems. This discrepancy can lead to safety and performance issues.
A closer look at the materials: GX60 vs. GX30
CTT Systems’ original pad with approved GX60 material
CTT Systems’ original humidifier pads are designed with GX60 material—a ceramic/active-carbon glass fibre composite specifically developed for aviation applications. This ensures optimal control over odours, bacteria, and pathogens, such as Legionella. Top aircraft manufacturers and relevant authorities, including the FAA and FDA, specified the tests needed to approve the CTT Systems pads.
PMA pad with GX30 material
Conversely, the PMA pads utilise GX30 material, a glass fibre composite that has historically been used only for static industrial applications. The GX30 material is discontinued outside the US and, more importantly, has not been approved by major aircraft manufacturers or subjected to all the rigorous testing required for aviation use.
Furthermore, the GX30 pad is designed to remain wet at all times during operation. The aircraft humidification system does not continuously rinse water through the pad; instead, it periodically sprays water onto it.
PMA’s potential safety implications
The humidification system is integrated into the duct and is part of the aircraft environmental control system (ECS). A blocked pad could compromise airflow to the flight deck, potentially leading to unsafe levels of carbon monoxide or carbon dioxide, or insufficient ventilation of hazardous smoke.
Munters´ study and findings of GX60 vs GX30
Munters, the world leader in evaporative cooling pad material, has conducted a comprehensive comparison between GX60 and GX30 media types, highlighting significant differences for this particular field of use in aircraft humidification systems:
Performance efficiency
GX60 has a lower pressure drop, making it more effective in systems where airflow resistance is a concern.
Material composition
GX60 is a ceramic/active-carbon composite media with minimal organic compounds, allowing it to operate effectively across a wider pH range (3-11). This makes GX60 suitable for varying water treatment conditions without degradation.
The GX30, primarily composed of glass fibre, has a narrower pH tolerance (6.5-8.5), which limits its applicability.
Odour and bacteria control
GX60 features active carbon for enhanced odour control and is tested against Legionella bacteria, ensuring safety against both air- and waterborne pathogens.
GX30 lacks these features, posing a risk in environments where odour control and bacterial safety are critical.
Structural integrity
GX60’s rigid structure prevents collapse under its weight when wet. This feature ensures consistent performance and durability of the GX60 in various operational conditions.
GX30 offers less structural stability.
Fire safety and global use
GX60 meets the highest fire safety standards, EN 13501-1 Class A1, and is utilised globally.
GX30 does not meet this standard.
Water treatment compatibility
GX60 can handle oxidising chemicals used in water treatment.
GX30 does not support such treatments, which can limit the ability to maintain hygiene standards in humidification systems.
The conclusion from Munters’ study
The study clearly outlines why GX60 media is superior to GX30, particularly for critical applications such as aircraft humidification. GX60’s enhanced material properties, ability to control odours and bacteria, structural integrity, and broader chemical tolerance make it a preferred choice for aviation and other sensitive environments.
Munters’ recommendation
Given the considerable differences in quality, testing, and certification, Munters strongly advises against using non-OEM humidifier pads. The safety, performance, and compliance risks associated with PMA pads do not justify the potential cost savings. Ensuring the use of OEM-approved materials, such as the GX60 pads, is essential for maintaining the highest air quality standards and ensuring safety onboard.
Humidifier Onboard with original pads
– developed for aviation standards and OEM compliance