Humidity in the air can wreak havoc on packed materials, causing corrosion and growth of mold. With temperature changes, condensation can be a major problem as well. While you can place a desiccant in the packaging to absorb moisture for a while, but desiccants eventually lose their effectiveness and need replacing. By knowing the level of humidity in a transit case or shipping container, you can take action before any damage occurs. This is where humidity indicator cards come into play.
What are Humidity Indicator Cards?
Humidity indicator cards are cards that are impregnated with materials that change color when indicated relative humidity is exceeded. Usually, it is a blotting paper that has been impregnated with cobalt (II) chloride base. Less toxic alternatives available in the market include other chemicals such as cobalt-free chloride base and special plastic films.
Humidity indicators are a relatively inexpensive way to indicate humidity inside any sealed packaging. They are available in many grades and used in various applications, especially military and semiconductors. The most common humidity indicator cards change color from blue to pink.
Color Changing Humidity Indicator Cards
Cobalt chloride blue when dry and turns pink in the presence of moisture. It is an excellent way to measure humidity. Chemists have engineered this color change to take place at various humidity levels with humidity indicators available in 10% increments – from 10% to 90% relative humidity.
Humidity indicator cards with cobalt care generally quoted as +/- 5% accurate at 75°F. At temperatures above 75°F, the indicator will show a slightly lower humidity than is actually in the case. At lower temperatures, it will read slightly higher. However, there is also some concern over the possible toxicity of cobalt chloride. While cobalt cards are regulated for use in Europe, cobalt-free indicators are available in the market.
Permanent or Irreversible Indicator Cards
While in most applications, you can use an indicator that shows the current level of humidity. However, in some situations, an irreversible or permanent indicator card is a better option. An irreversible indicator card shows the maximum humidity inside a container. This might be useful for long term storage and shipping. Sometimes termed “color stain” elements, irreversible indicators turn orange or blue when exposed to excess humidity. Once the color changes, a maximum humidity indicator cannot be reused and must be replaced.
Applications of Humidity Indicator Cards
- Electronics components and electrical equipment
- Automobiles and automotive parts
- Glass and related products
- Metals and fabrications made from metals
- Wooden articles, furniture, pallets, and crates
- Food and packed products
- Agriculture and commodity products such as tea, coffee, rice, pulses
- Bulk chemicals, minerals, etc.
- API, pharmaceuticals, bulk drugs
- In-home for your various items like electronics, beddings, quilts, shoes, cupboards, etc.
If you’re looking to buy humidity indicator cards, AgileNobel is your place to go. In addition to humidity indicator cards, the company also offers a wide range of commercial chemicals including spodumene, desiccants, oxygen absorber, oxygen scavenger, tyvek paper, water treatment clay, lithium hydroxide, and more.
AgileNobel 