Potential contaminants like corrosion, mildew and mold all need moisture to thrive. As a result, many companies invest in moisture-controlling packaging to prevent excess buildup. Humidity indicator cards (HICs) provide a way for businesses to monitor their packaging solutions for increased peace of mind about the moisture levels within them.
What Are Humidity Indicator Cards?
HICs are heavyweight paper stock featuring color-changing chemicals that indicate the humidity levels in a container. As the interior moisture level rises, the darker blue dots will transition from blue to pink. These cards can detect humidity at various ranges but do not provide a precise percentage. Instead, they serve as a guide about the maximum moisture existing within a package.
HICs provide companies with insights about their products as they alert you if moisture has entered your package. This indicates the quality or your moisture-related protective packaging and can tell you if you need to add other materials, such as moisture-absorbing desiccants, to improve performance.
Types of Humidity Indicator Cards
Depending on the moisture levels that you need to monitor, you may require different types of humidity cards, including:
- Three spot HICs: These detect 30%, 40% and 50% humidity levels.
- Four spot SMD Himitector cards: These are specifically designed for packaging surface mount devices as they can detect 10%, 20%, 30% and 40% humidity levels.
- Six spot HICs: These have six spots that can detect moisture levels ranging from 10% to 60%.
- Indicator plugs: These can used in flexible barrier bags and indicate the humidity levels within a sealed container without opening it.
How Do Humidity Indicator Cards Work?
Humidity indicator cards contain spots that are impregnated with a moisture-sensitive chemical solution, such as a blue cobalt chloride base. When you expose this chemical to moisture, the crystals within rearrange themselves to accommodate the water. With more H2O, they transform into cobalt chloride dihydrate, which is purple. When you add more water, it becomes a hexahydrate, which is pink.
This process is reversible as the crystals revert back to their blue anhydrous form when the water is removed.
How to Read Humidity Indicator Cards
Using a cobalt chloride base in HICs allows the viewer to see how much moisture has entered a container based on the color of the spots on the card. Each spot contains the cobalt chloride base with a specific humidity level.
All the spots should be blue before placing your card in a container. Blue spots mean the card hasn’t come into contact with water, such as from the air. If you open your package after some time and one or more spots are purple or pink, you know there is humidity in the package. For example, if the 30% and 40% spots on a three-spot HIC card are pink, you know there is 40% humidity in the container.
Humidity Indicator Card Accuracy
HICs can only indicate the maximum humidity level and not the exact humidity percentage. This is sufficient for most use cases as the humidity level in the container needs to stay below a certain threshold. Most goods can be stored below 40% humidity as corrosion, mildew and mold do not occur at this level.
Humidity Indicator Card Lifespan
You can only reuse HICs if they are reversible, but even then, you should only use one a maximum of three times. Before reusing a card, ensure all the dots have turned back to blue. Irreversible maximum HICs will not turn back to blue and cannot be reused.
When stored in a cool, dry place away from sunlight, most sealed HICs have a shelf life of three years.
The Impact of Humidity Indicator Cards on Packaging and Quality of Goods
When you go to great lengths to seal your packages, you want to know that they work as intended to keep moisture out. You can use humidity indicator cards to prevent a wide range of issues and ensure your packaging remains effective.
Contribution to Safe and Secure Packaging
Moisture can deteriorate the packaging you use for your products. Metal cans will rust and paper packaging, such as cardboard boxes, will start to break down. With HICs, you’ll know if your packaging is working to keep your products safe and secure.
Ensuring Product Integrity
Product integrity measures how well the container or packaging protects the product inside. You’ll know if a product containing moisture, such as cans of beans or juice, has leaked when you use a humidity indicator card. If there is a leak and the product integrity has been compromised, the spots on the card will be pink.
Impact on Quality of Packaged Goods
When moisture gets into packaged goods, it causes reactions that degrade the quality of the product. If water gets into electronics, the corrosion can permanently damage the components and you’ll no longer be able to use them. Humidity in food products affects the product’s taste, texture and safety. Mold and mildew will make the food unsafe to eat, while moisture can make powders cakey, sugary items sticky and bread soggy. Using an HIC can ensure that the quality of the product remains intact and allow for swift action if humidity is present.
Uses of Humidity Indicator Cards in Different Industries
Businesses in multiple industries can benefit from humidity indicator cards, including:
- Trading and shipping companies: HICs can indicate the maximum humidity reached across long ocean voyages. Humidity levels must remain low to protect the cargo from moisture damage.
- Food service companies: HICs help ensure your packaging has accurately preserved food so it’s safe for consumption.
- Military agencies: HICs help determine whether humidity levels are appropriate for uniform and document storage to prevent mildew or mold growth. They can also prevent corrosion on surface mount devices and weapons.
- Electronics manufacturers: HICs promote meeting industry goals for low-humidity packages to ensure product quality and prevent corrosion.
- Cultural organizations: HICs are compatible with sealed frames or cases to detect potential moisture issues that could damage exhibits and artifacts.
Buy Humidity Indicator Cards From Edco
Edco Supply Corporation has been a trusted supplier of humidity indicator cards since 1954. Our effective packaging solutions come from decades of industry expertise and a passion for superior quality. We proudly serve businesses throughout the U.S. and Canada, and all our humidity-detection solutions meet relevant military specs for defense contractors.