Guide to Using Humidity Indicator Cards

Maintaining consistent humidity levels is crucial to ensuring product quality and shelf life in many industries. From electronics to pharmaceuticals, controlling moisture levels can prevent product damage.

Humidity Indicator Cards is a packaging solution for monitoring humidity within packaging. This guide provides comprehensive insights on using HIC to keep products safe and in an optimal condition.

What Are Humidity Indicator Cards (HICs)?

HICs are small, paper-based cards that visually indicate the relative humidity (RH) levels within a sealed environment. The cards feature chemically treated spots that change colour as humidity levels change. This colour change provides a clear and easy-to-read visual indication of moisture levels. HICs typically display a sequence of colour-coded spots with each spot corresponding to a different humidity level. Their straightforward design allows users to easily assess the conditions inside a packaging.

How HICs Work

HICs’ chemically treated spots correspond to a different humidity level, such as 10%, 20% and 30%. When the ambient humidity reaches or exceeds the level indicated by a particular spot, the colour changes, usually from blue to pink or brown to green, depending on the specific chemicals used. This colour change is the result of a chemical reaction between the moisture in the air and the hygroscopic materials in the indicator spots.

This table outlines the importance of humidity control and their role in various industries and applications:

Choosing the Right HICs

Selecting the appropriate HICs results in accurate and reliable monitoring of humidity levels in various environments. When choosing a HIC, consider the following factors to ensure it meets specific requirements.

Types of HICs

There are two main types of HICs: Cobalt-Dichloride and Cobalt-Free. Each type has specific characteristics and applications. It is essential to understand their differences when selecting the appropriate card.

• Cobalt-Dichloride HIC: These cards contain cobalt dichloride, a chemical that changes colour from blue to pink when exposed to moisture. These cards are highly reliable and provide a clear, distinct colour change, making them easy to read.
• Cobalt-Free HIC: These cards were developed in response to the regulatory and environmental concerns associated with cobalt dichloride. They use alternative chemicals that are less hazardous and more environmentally friendly. The most common alternatives include copper-based and silica gel-based indicators.

Humidity Range

Different cards are designed for monitoring different relative humidity ranges (RH). Here are some standard humidity ranges and their applications:

• Low Humidity Range (5% to 15% RH): Suitable for highly sensitive electronic components and specific pharmaceuticals that require very low moisture levels.
• Medium Humidity Range (20% to 60% RH): Commonly used in general electronics, food packaging, and specific pharmaceuticals where moderate humidity control is needed.
• High Humidity Range (65% to 90% RH): Typically used for applications where higher moisture levels can be tolerated, such as in certain industrial and agricultural settings.

Size and Shape

HICs come in various sizes and shapes to fit different packaging and storage requirements. When selecting a HIC, consider the following:

• Available Space: Ensure the card fits comfortably within the packaging or storage container without obstructing or interfering with the product.
• Visibility: Choose a size and shape that allows easy reading of the humidity levels without removing the card from the packaging.
• Application Specificity: Some HICs are designed for specific applications, such as flat cards for easy placement in document storage or curved cards for cylindrical containers.

Compliance with Industry Standards

Many industries have specific standards and regulations regarding humidity control and monitoring. Compliance with industry standards ensures that HICs provide reliable and approved humidity monitoring process. This approach facilitates regulatory adherence and quality assurance.

• MIL-I-8835A: A standard commonly used in military and aerospace applications.
• IPC/JEDEC J-STD-033: A standard for handling, packing, shipping, and using moisture / reflow-sensitive surface-mount devices.
• FDA Regulations: Ensures the HIC complies with FDA guidelines and requirements for pharmaceuticals and medical devices.

How to Use Humidity Indicator Cards

It is important to understand the correct way of using HICs for accurate humidity monitoring for protecting sensitive items. Follow this step-by-step guide to use HICs effectively in various applications:

1. Preparing the Packaging Environment

Before placing the HIC in the packaging, it is essential to first prepare the environment to collect accurate readings. This step ensures humidity levels are well maintained for optimal quality assurance for the items being stored or shipped out.

• Clean the Area: Ensure the packaging environment is clean and free from contaminants that could affect the HIC or the sensitive items.
• Control Initial Humidity: If possible, use a desiccant to reduce the humidity level in the environment before sealing the package.
• Check for Damage: Examine the HIC for any damage or discoloration prior to use.

2. Placing the Humidity Indicator Card

Proper placement of the HIC is crucial for effective humidity monitoring.

• Select the Location: Choose a location inside the package where the HIC readings will be easily visible and accessible without opening the package. Common placements include near the top or at the side of the container.
• Avoid Direct Contact: Ensure the HIC does not come into contact with the moisture-sensitive item. Place the card in a small, protective pouch or sleeve if necessary.
• Secure the Card: Use tape or an adhesive strip to secure the HIC. This prevents the card from shifting during transportation or storage.

3. Sealing the Package

Once the HIC is placed in an appropriate position, move on to seal the packaging with a vacuum sealer to maintain a controlled environment.

• Close the Package: Carefully seal the package and ensure all openings are tightly sealed to prevent moisture from entering.
• Use Desiccants: Consider adding desiccants to the package to help maintain low humidity levels.
• Inspect Seals: Double-check all seals and lids and ensure they are secure and airtight.

4. Reading and Interpreting the Results

Regular HIC inspections will help monitor the humidity levels and safeguard the stored or sensitive items.

• Observe Color Changes: Check the HIC regularly for any color changes.
• Take Action if Needed: If the HIC indicates that the humidity level has exceeded the safe range, immediately reduce the humidity. This may involve adding more desiccant packs, resealing the package, or moving the items to a different environment.

Storing and Handling HICs

Proper storage and handling of HICs are required in maintaining their accuracy and reliability. Follow these guidelines to ensure that the HICs remain effective:

Proper Storage Conditions

Properly stored HICs is important for ensuring HICs remain in an optimal condition.

1. Controlled Environment: Store HICs in a dry, temperature-controlled environment. Excessive moisture and extreme temperatures can degrade the chemicals used in the indicator spots.
2. Sealed Packaging: Keep HICs in their original, sealed packaging until they are ready to be used. The packaging is designed to protect the cards from ambient humidity and contamination.
3. Desiccants: Store HICs with a desiccant pack inside an airtight container.
4. Away from Direct Sunlight: Avoid exposing HICs to direct sunlight or other sources of UV radiation.
5. Temperature Range: Store HICs within a specific temperature range advised by the manufacturer. This is typically between 15°C and 25°C (59°F and 77°F).

Handling

Careful handling is required to ensure the effectiveness of HICs:

1. Clean Hands: Handle HICs with clean and dry hands to prevent contamination. Oil, moisture, and dirt from your hands can contaminate the indicator spots.
2. Minimise Exposure: When removing HICs from their packaging, take precaution to minimise the time the cards are exposed to ambient air. Prolonged exposure can cause the indicator spots to react prematurely.
3. Avoid Physical Damage: Handle the cards gently and avoid bending, tearing, or damaging them.
4. Proper Placement: Ensure that the HIC is placed within the package or storage environment where it will not be subjected to physical stress or contaminants.
5. Seal After Use: To maintain its integrity, ensure it is resealed in an airtight container with desiccant.

Conclusion

Humidity control is crucial for protecting valuable and sensitive items from moisture. HICs offer a simple and cost-effective solution for monitoring humidity levels within sealed environments. The cards allow for timely intervention if ideal conditions are not met. HICs are required for adherence to industry standards on ensuring product quality.