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In the aerospace and defense industry, the demand for conforming parts and performance on demand is incredibly high. Whether deploying a fire suppression bottle in a cargo hold or activating an emergency egress system, it is imperative that cartridge-actuated devices (CADs) and propellant-actuated devices (PADs) perform instantaneously after years of dormancy. However, the chemical stability of these pyrotechnic devices isn’t guaranteed if they’re mistreated. Improper storage — characterized by fluctuating temperatures, uncontrolled humidity or physical shock — can degrade the propellant mix, leading to “duds,” misfires or dangerous malfunctions.

To maintain the airworthiness of your inventory and the safety of your crew, strict adherence to environmental controls and handling protocols is mandatory. This guide outlines the essential storage requirements, handling precautions and regulatory standards necessary to preserve the life and reliability of your aircraft pyrotechnics.

Overview of Pyrotechnic Device Storage Requirements

Before discussing the environment, it’s critical to understand what is being stored. Aircraft pyrotechnics — specifically CADs, PADs, squibs and ignition cartridges — are energetic devices that require respect. To maintain safety, facilities must establish designated safety zones and follow cartridge storage guidelines. These storage magazines or lockers must be fire-resistant, well-ventilated and strictly separated from other flammable materials such as fuels, oils or solvents.

Storage protocols must also adhere to compatibility groups. While many aircraft squibs are often classified as 1.3 or 1.4 (S or C) explosives, it’s vital to store compatible explosive classes together. For instance, bulk propellants should generally be separated from sensitive detonators unless specific packaging allows for co-storage.

Learn more about how CAD/PAD devices work and their uses.

Temperature, Humidity and Environmental Controls

The chemical composition of a pyrotechnic device is sensitive to its environment, even while in storage. It must be treated with the utmost respect and care to prevent fatal injuries. Additionally, to ensure the device functions as designed during an emergency, three main factors must be heavily controlled during storage operations:

Temperature Stability

Extreme heat is a primary enemy of energetic materials. Storage areas should be maintained at a controlled room temperature, typically between 60° Fahrenheit and 80° Fahrenheit, avoiding extremes above 100° Fahrenheit or below freezing unless the specific device is rated for such conditions.

The risk: Thermal cycling, or rapid heating and cooling, can cause propellant grains to expand and contract, potentially leading to cracks that alter the burn rate or cause seal failures. Essentially, temperature instability during storage or in an operating environment can cause a pyrotechnic device to behave in an unanticipated or uncontrolled manner. Examples include failing to initiate, initiating with lower than needed energy or outright detonating in an uncontrolled manner.

Humidity Control

Moisture is the silent killer of pyrotechnic reliability. High humidity can lead to the oxidation of electrical contacts (bridgeswires) or the degradation of the propellant mix itself. However, if the humidity is too low, there’s a risk of electrostatic discharge (ESD) while handling. Without enough water in the air, workers handling the ordnance can generate static electricity on their bodies, which can accidentally initiate the device. This situation is more likely to happen when workers aren’t following proper ESD mitigation protocols.

  • The solution: Storage lockers should be equipped with desiccants and humidity indicators. If the humidity indicator on a hermetically sealed package shows exposure, the device should be considered suspect.
  • Standard reference: The latest U.S. Department of Defense standard for testing military and commercial equipment against environmental stresses, MIL-STD-810H, outlines specific testing methods for humidity resistance, ensuring devices can withstand these stressors if properly packaged. The Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) Explosive Storage Requirements are also critical for handling and storing explosive materials.

Vibration and Shock

Storage areas must be free from excessive vibration. Constant low-level vibration, such as near heavy machinery, can cause propellant grains to settle or fracture over time, changing the explosive characteristics of the device.

Learn more about environmental testing for cartridge-and propellant-actuated devices.

Inventory Management and Security Measures

A robust inventory system is the first line of defense against expired or unsafe devices.

  • FIFO protocol: Implement a “First In, First Out” (FIFO) management system. This approach ensures solder stock is used before newer shipments, preventing valuable inventory from expiring on the shelf.
  • Shelf life vs. service life: It’s critical to distinguish between these two terms. Pyrotechnic shelf life for aircraft refers to how long a device can remain in storage in its original package. Service life refers to how long it can remain installed on the aircraft.
  • Documentation: Maintain strict logs of lot numbers, date of manufacture and expiration dates. Missing documentation often necessitates the disposal of perfectly good units because their heritage can’t be verified. Explore more about CAD/PAD safety data sheets and EX approval documentation.

Handling Precautions and Packaging Guidelines

The moment a device is removed from storage is when it’s most vulnerable. Personnel handling these devices must be trained in specific safety protocols, including minimum humidity requirements, wrist and ankle grounding, workstation and tool grounding, and wearing PPE, such as cotton clothing and conductive safety shoes.

Below are some other essential device handling best practices.

ESD

The human body acts as a capacitor, capable of storing static electricity that can inadvertently ignite sensitive squibs and other chemical compound mixtures or devices.

Protocol: Technicians must always wear grounding straps and use conductive mats when handling exposed devices. Synthetic clothing, like nylon or polyester, generates static charge and is prohibited around these devices. Wearing cotton clothing is an industry standard and requirement. Learn more about managing ESD sensitivity levels in aircraft electronics.

Original Packaging

Devices must remain in their hermetically sealed barrier bags and original shipping containers until the exact moment of installation. This packaging is designed to meet MIL-STD-2073-1E standards, providing essential protection against moisture, physical impact and ESD.

Physical Handling

“Handle like eggs” is the golden rule. Drops, impacts or rough handling can damage the internal bridgewire and the grain structure, or compromise the hermetic seal, rendering the device unsafe or inoperable. The ordnance is so sensitive, in fact, that it shouldn’t be passed between personnel by hand. It should be placed on a table for grounding by one worker before the other picks it up.

Regulatory Compliance for Storage (FAA and MIL Standards)

Compliance isn’t just about safety — it’s a legal requirement. Here are the most important regulations and guidelines for safe storage of pyrotechnic devices.

FAA Regulations

Federal Aviation Administration (FAA) airworthiness directives strictly govern the maintenance of pyrotechnic safety systems, such as fire bottles and ejection seats. Installing an expired or improperly stored device renders the aircraft unairworthy.

Transport Regulations

If moving inventory between hangars or facilities, operators must comply with 49 CFR Part 175 regulations and U.S. Department of Transportation (DOT) regulations regarding the carriage of hazardous materials. These rules cover labeling, packing and declaring dangerous goods.

ATF and DOD

Storage magazines often must meet specific construction requirements set by the ATF and the Department of Defense (DOD) to ensure security blast containment.

Tips for Long-Term Device Preservation

To maximize the usable life of your inventory:

  • Conduct visual inspections: Regularly check storage containers for damage. Look for corrosion on pins, dents in casings or compromised moisture barrier bags.
  • Ensure chemical isolation: According to federal regulations, pyrotechnics can’t be transported on the same vehicle or stored anywhere near corrosive chemicals, acids or cleaning agents. Off-gassing from these materials can compromise device seals or cause a fire or explosion.
  • Maintain reliability assurance: Proper storage is the only way to maintain the confidence level of the device. Applied Energy Technology Corporation performs rigorous in-process testing to ensure reliability, but reliability must be preserved through good stewardship once the device leaves the factory.

Why Trust Applied Energy?

When safety is on the line, the source of your pyrotechnics matters. Applied Energy has been a leader in the field since 1978. We offer:

  • Decades of experience: We have over 40 years of experience in the design, development, qualification and manufacture of life-support pyrotechnic and explosive components.
  • Certified quality: We’re ISO 9001:2015 certified, ensuring product quality and consistency, and approved by the DOD, ATF and FAA.
  • Custom solutions: Whether you need a standard fire extinguisher cartridge or a custom solution for an obsolete system, AETC provides high-quality components with economical pricing and on-time delivery.

Get Tailored Solutions From AETC Today

The proper storage of aircraft pyrotechnics isn’t just a logistical task — it’s a critical safety discipline. By controlling the environment, managing inventory and adhering to strict handling protocols, you ensure that when a device is called upon to perform, it does so without failure.

Do you have questions about shelf-life extension, replacement cycles or safe storage practices? Contact Applied Energy today to learn more about our products or discuss your specific pyrotechnic needs.