Humidity Indicator Cards
Humidity Indicator Cards provide external monitoring of humidity levels inside containers and packaging, they are available in both reversible and non-reversible technologies depending upon the specific application. They usually change colour from blue to pink to denote a dry to wet humidity change, which use either cobalt dichloride (CD) or cobalt dichloride free (CDF) impregnated solutions. It is possible to have humidity indicator cards with cobalt free solutions (CF) that change colour from brown to green as they go from a dry to wet humidity. The most common humidity indicator cards are rectangular and consist of three to six levels of indication.
Humidity Indicator Cards are primarily used within the packaging industry, most used with electronics and in combination with desiccant bags.
It is essential when choosing the correct indicator card that it relates directly to the type of desiccant bag to be used within the application. This Desiccant Bag is also important for which ever product you are packaging as the type of desiccant used will have different properties and drying levels.
When determining the amount of desiccant and correct humidity indicator card to use, it is vital to consider the Moisture Vapour Transmission Rates (MVTR) through the materials you are using for your package or container. Our Technical Team have extensive data on the MVTR of various materials; this data has been compiled over decades using our own internal VIPOR desiccant calculation software. This is extremely important for Diagnostics Packaging and Military Packaging where very sensitive products are stored or there is a requirement for long term storage.
The 5/10/60 card is a unique product specifically designed for the Diagnostic packaging industry, it has two relative humidity levels at 5% & 10% which are reversible and one level at 60% relative humidity that in non-reversible, this give a visual indication of when a 60% humidity level have been exceeded within your packaging even if the humidity has reduced again and the 5% & 10% are still blue.
All Humidity Indicator Cards can be supplied compliant to DEF STAN 66-14, DEF STAN 81-132, MIL-I-8835 and JEDEC J-STD-033 standard.
Also available are humidity indicator discs which are designed to be used within Humidity Indicator Plugs. These humidity indicator discs can be supplied with multiple levels also, up to a maximum of 4 per disc and are available in varying sizes with either pie shaped or spot shaped segments, some examples below.
Maximum Indicators
Non-reversible humidity indicator cards or Maximum Indicator cards are designed for applications which require monitoring the maximum humidity levels attained when exposed during storage or transit. Our maximum humidity indicator cards have each level of humidity represented by a blue crystal that dissolves to create a large blue spot that clearly indicates the relative humidity level that has been reached. Custom cards are available on request.
The TA378-HC-MHI is designed for the long-term storage of sophisticated military and electronic equipment. A non-reversible or maximum humidity indicator disc often superior to standard humidity indicator discs as it maintains a record of past conditions. The elements work by staining a white disc a brilliant orange (turning later to dark brown) when it is exposed to humidity above 55%. These elements can be installed in a standard TA456 Observation Window housing.
