FAQ’s

Time Indicators

What is the process for getting a custom Timestrip®?
If the Timestrip® is not being integrated into the product itself, and is being used as a ‘label’, then it is very straightforward. We need to know:
  • Duration of the Timestrip® (from 5 minutes to several years) and the temperature environment it will be calibrated for, such as room temperature or refrigerator.
  • Graphic concepts, layout and branding guides Adhesive requirements. (What will it be stuck to? Do you need adhesive? Will you use a carrying card? Do you want a key chain?)
  • If the Timestrip® is being integrated into the  product itself, the first step is for us to look at the actual product or CAD design. We are happy to supply a Non-Disclosure Agreement to maintain confidentiality. We will then propose a feasible design for the Timestrip®.
We have our own design facility so creating the surface graphics, working on design layouts and finalising artwork is all part of the service. We’ll need your logo artwork in a vector file format like .ai or .eps, (not a .jpg or bitmap) and any brand guidelines or draft layouts you can provide. If you need to match production inks to brand colours we can send you a swatch book to specify the closest colour match. You’ll be pleased to know we never go to full print and production without clients approving digital proofs first.
What are Timestrip® Time Indicators?
Timestrip® time indicators are patented, single use disposable visual reminder that can be stuck directly onto a product or device. Each Timestrip® acts as a simple visual reminder to replace an expired product or carry out a task, like maintaining a machine or checking results from a test. We have a stock range of products that includes from 30 minutes up to 12 months and many common reminder times in between.  Subject to minimum order quantities, Timestrips® can be custom made for any elapsed time period between 5 minutes and 4 years.
Why does Timestrip give away 1 or 2 free products with every pack of 100?
Because we like our customers! You can use these free products for testing, training, validation, or just to save money. In the unlikely case any got damaged along the way or someone just wanted to try one, there is no need to get in touch, although we're always happy to hear from our customers. Personally, we think that all companies should give stuff away for free!
Can Timestrips be used in any direction / orientation?
Yes.  Orientation has no impact on the way it works.
How do Timestrip time indicators work?
A tinted liquid gradually moves through a white viewing window at a pre-calibrated rate. You can read how long the Timestrip® has been active by seeing how far the colour has progressed along the time markers that are printed by the window. When the colour reaches the end of the window, the full time has elapsed and this is the signal to carry out your task or replace a product. When you want to start monitoring elapsed time, activate the Timestrip® by fully squeezing the button between a thumb and finger. An activation line will appear to show that the Timestrip® is working. This line typically appears in a few seconds but can be up to a few minutes in Timestrips® that measure in months and years. Stick the Timestrip® on or near to the product or device it is monitoring and look at it occasionally so you can see when time is up. Dispose of the Timestrip® once the colour has reached the end of the window and activate a new Timestrip® to start monitoring the next product or device.
How do I know if I activated the Timestrip®?
After squeezing the button flat a line will emerge in the window to show that the Timestrip® is activated. If the activation line is already present before you activate it, then discard that indicator and take another.
Is the liquid dye safe?
Yes. Please see our MSDS for further information. In the unlikely event that the liquid leaks from the Timestrip® and comes into contact with skin, simply wash with soap and water. If the liquid comes into contact with eyes, rinse immediately with plenty of water and seek medical advice.
What if I find an activated indicator in the bag of 100?
This is highly unlikely, but if so, it is likely due to physical force in transit. We ship many of our products in bags, to minimize shipping costs and packaging materials. Discard the indicator and select another. There is no need to contact us, as we ship a few extra free products in every 100 count anyway.
Are they waterproof?
Timestrips® are not designed to be submerged in water, but they are very splash-proof and can be immersed in water for short periods without any effect.
What is the shelf life of a Timestrip® time indicator?
Timestrips® can be stored for 3 years after they leave our factory and require no special storage conditions.  Some indicators can have much longer shelf-lives, depending on their configuration.
What custom shapes are available?
This depends on the duration of the Timestrip®, but our standard format is 19 x 40mm. Subject to the life of the Timestrip® we also can tool-up to create completely new shapes for you, subject to technical limitations.
Are there any printing constraints?
Timestrips® are printed by using a masking effect over the timer so we have to use special colours. This means that we work better with darker colours and cannot achieve pure whites and yellows. A good guideline is to use colours with 10% black equivalent to them. If your project is for higher volume, we are able to use a different type of print process, which enables more options on the lighter colours.  We will help you every step of the way with developing a great look for your personalised time indicator.
Can we receive custom made samples?
Due to the manufacturing processes involved it is not possible to supply custom made, fully functioning samples in small quantities. We provide digital proofs, showing ‘before’ and ‘after’ read-outs so you can see what an active Timestrip® will look like and we can also send you a variety of existing products with artwork, if you need to show functionality and check dimensions. If actual samples of your finished product are absolutely necessary, we would have to do a proper production run with associated costs and lead times.
How much does customising a Timestrip® cost?
This depends on how many elements are customised and to what extent. For example, using a stock 3 month Timestrip® as the basic product and changing only the graphic print will be less additional cost than a bespoke shape, graphic and elapsed time. Each project is quoted according to volume, specification and lead time requirements. A one off set-up cost will cover tooling and development and on-going production costs will depend on the complexity of the specification.
Can you add our logo to the Timestrips?
Yes, that is possible on custom products, subject to minimum order quantities.  In addition to printing your logo and messaging, a small, discreet Timestrip® logo will also be placed on the product, due to copyrighting. We proudly co-brand with some of the best and most recognised brands in the world. It is not possible to post-print a logo to an existing stock time or temperature indicator.
Will Timestrip® tell me when a product is no longer fresh or usable?
Timestrip® only records the passage of time after it is activated. It can be used as a reminder for you to check quality or fitness of purpose of a good or material but it does not monitor anything other than the progress of time.
Can you use different colored liquids?
Our Timestrip® colourant is red for indicators that monitor days to years, and blue for Timestrips® that monitor minutes to hours.
Can I have a fully customised Timestrip®?
Yes! Our stock products take advantage of lower unit costs and lead times but if your requirements exceed 100,000 units per order we can work with you to create a fully customised product. Most elements of Timestrip® can be adapted to suit your needs: different shapes, sizes, customer colours and logos; elapsed time periods from 5 minutes to several years; adapted for a different average temperature environment; supplied with a wide range of perm-peel or permanent adhesives or without adhesive; supplied in a key chain, on a roll, loose, in poly bags or custom packs; on a carrying card. We can work with your product design teams to explore how custom products can be integrated into products, replacement parts or devices with or without auto-activation. Integration encourages compliance with recommended replacement cycles and thus increases purchase frequency. A small Timestrip® logo appears on all our Stock and Custom products.
Is the liquid safe?
Yes, and it is a tiny amount and fully encapsulated within the product.  Please see our MSDS for further information. In the highly unlikely event that the liquid leaks from the Timestrip® and comes into contact with skin, simply wash with soap and water. If the liquid comes into contact with eyes, rinse immediately with plenty of water and seek medical advice
Is accuracy affected by temperature or altitude?
Timestrips® are accurate to within +/- 15% depending on the model, provided they are used in line with the stated average temperature. If the product is stored at a higher than intended temperature the colour will advance at a faster rate than expected, and for lower than intended temperatures at a slower rate. For detailed technical information please contact us. Altitude does not affect accuracy.
What are your Acceptable Quality Limits (AQL’s)?
The Accepted Failure Rate is based on ANSI/ASQC Z1.4 (formally MIL-STD-105E) Level II Normal Inspection. Packs are over shipped by 2-3 units per 100 to cover this AQL. Central to this process are tests against defined specifications for; how quickly the dye progresses through the membrane, environment sensitivity (high heat and vacuum tests to check resilience to harsh conditions during shipping) and also the accuracy of the threshold melting point. A full pack of release reports is provided with each shipment. Further details are available on request.
Is the liquid safe?
Yes.  Please see the product MSDS on our website for further information. We only use food-grade oils and non-toxic colourants in our formulation. In the unlikely event that the liquid leaks from the indicator and comes into contact with skin, simply wash with soap and water. If the liquid comes into contact with eyes, rinse immediately with plenty of water and seek medical advice.

Blood Temp 10

What is Blood Temp 10?
Timestrip® Blood Temp 10 a single use temperature indicator in a self-adhesive label format.  It provides proof of meeting AABB Standards and the FDA’s CFR 600.15(a) for monitoring temperature of whole blood during transportation and storage. FDA 510(k) #BK150289
Do I need to pre-condition Blood Temp 10 prior to activation?
Absolutely not! Unlike some other threshold temperature products, Blood Temp 10 do not require pre-conditioning. Just activate Blood Temp 10 at any temperature above 10°C/50°F as you cannot squeeze the dye out of the blister if it is in solid form. You then simply need to adhere the Timestrip onto a pre-chilled blood bag, whose temperature will immediately solidify the dye and track any 10 degree temperature breaches.
Why choose Blood Temp 10 over other blood bag indicators?
You really need to try them (for free, of course) to really appreciate how easy they are to use.  Timestrip Blood Temp 10 have the same or better accuracy than other indicators on the market, are FDA cleared, but where they are different from other indicators:   Blood Temp 10 are simpler and faster to store, to use, and even cost a bit less, saving you time, money and effort.
Why does Timestrip give away 1 or 2 free products with every pack of 100?
Because we like our customers! You can use these free products for testing, training, validation, or just to save money. In the unlikely case any got damaged along the way or someone just wanted to try one, there is no need to get in touch, although we're always happy to hear from our customers. Personally, we think that all companies should give stuff away for free!
Can Timestrips be used in any direction / orientation?
Yes.  Orientation has no impact on the way it works.
Why does the activation window turn dark green, but then a lighter green when back in the fridge?
That is normal, and as it should be. It goes a bit lighter green because the liquid inside has solidified and contracts slightly within the pore structure, making it appear a lighter shade.
Do Blood Temp Products have any special storage requirements before activation?
No, unlike some other blood bag temperature indicators, Blood Temp 10 can be stored at ambient temperatures and activated only when needed.
Do Blood Temp indicators have a shelf-life?
The expiry date is provided for each batch of products supplied.  You will find it on a label on each box together with the batch coding we use for traceability.
What type of adhesive is used?
The Blood Temp 10 adhesive is intended for labels to be used on blood bags. Request the MSDS for more details.
Why is there an activation window and a breach window?
The activation window gives an immediate confirmation that the indicator is armed as it turns from yellow to green. If this doesn’t happen immediately, then fully re-squeeze the button between thumb and finger. The breach/indication window (white with a red border) is separate so that you can clearly see if there has been a breach of the 10°C/50°F temperature threshold. If no breach has occurred the window will remain white. It will turn blue if there is a breach.
What does a partial colouration of the indication window mean?
Any blue colouration of the indication window (partial or full) denotes a temperature breach of 10°C.
What if one of the indicators in the box is showing the indication window already blue before I’ve squeezed it?
If stored under the correct conditions, this is highly unlikely to happen, but if it does, the built-in activation window lets you know it. If this happens, don't use the indicator and select another. There is no need to contact us, as we ship 1 or 2 extra indicators per pack free of charge anyway.

Timestrip® PLUS

Can Timestrip application be automated and integrated into production lines?
Yes, this is one of our strongest points of differentiation vs. other products.  Timestrip Indicators can be loaded bulk, orientated and ready to be custom applied and even activated inline if the application warrants it.  The video shows one of our solutions. Production Line Feeder
Why does Timestrip give away 1 or 2 free products with every pack of 100?
Because we like our customers! You can use these free products for testing, training, validation, or just to save money. In the unlikely case any got damaged along the way or someone just wanted to try one, there is no need to get in touch, although we're always happy to hear from our customers. Personally, we think that all companies should give stuff away for free!
Can Timestrips be used in any direction / orientation?
Yes.  Orientation has no impact on the way it works.
Are they waterproof?
Timestrips® are not designed to be submerged in water, but they are very splash-proof and can be immersed in water for short periods without any effect.
Is the liquid safe?
Yes, and it is a tiny amount and fully encapsulated within the product.  Please see our MSDS for further information. In the highly unlikely event that the liquid leaks from the Timestrip® and comes into contact with skin, simply wash with soap and water. If the liquid comes into contact with eyes, rinse immediately with plenty of water and seek medical advice
Can you provide Timestrip® PLUS on rolls?

Products are supplied loose in poly bags as standard. Subject to a premium and technical parameters, they can also be provided on rolls for integration into packaging lines or in boxes.

Can I get a false positive indication?
If the indicator is correctly activated false positives are extremely unlikely as the blue dye can only melt at or above certain temperatures.  It is important to lower the indicator to its STOP temperature after activation and only attach it to a product, carrying card or material that is already at or below the STOP temperature to avoid premature indication.
What are your Acceptable Quality Limits?
The Accepted Failure Rate is based on ANSI/ASQC Z1.4 (formally MIL-STD-105E) Level II Normal Inspection.  For Timestrip® PLUS the AQL is 0.65%.  Packs are over shipped by 2-3 units per 100 to cover this AQL. Timestrip® PLUS indicators go through extensive quality checks before they are shipped. Central to this process are tests against defined specifications for; run-time accuracy (how quickly the dye progresses through the membrane), environment sensitivity (high heat and vacuum tests to check resilience to harsh conditions during shipping) and also the accuracy of the threshold melting point.  A full pack of release reports is provided with each shipment.  Further details are available on request.
How can I use Timestrip® PLUS?
They are suitable for many situations when elevated temperatures can create problems for a product. Common applications are frozen or chilled foods, medicines, vaccines, adhesives and chemicals. A common use is to identify the elapsed time of temperature abuse during shipping. Another is for products which are taken repeatedly in and out of their ideal storage conditions for temporary use, like lab chemicals. One or two excursions might not be problematic, but Timestrip® PLUS shows the cumulative time of all excursions and this can be used to trigger a timely replacement of the product.
What is Timestrip® PLUS?
It is a single use temperature indicator in a self-adhesive label format. It indicates if temperature has risen to breach a defined threshold and it records the cumulative elapsed time of all such breaches. Each product in the range is engineered to respond to a different threshold temperature so customers can choose the product that best suits their needs.
Timestrip® PLUS compare with data loggers?
There are fundamental differences. Data loggers are expensive and typically are designed to go on large shipments. They are not an immediate tool as they need to be returned/connected for the data to be read and acted on, and they have to be used repeatedly to justify the expense. They also require power. Timestrip® PLUS indicators are less expensive, require no power, are single use and can be instantly read by the end user. They have unique serial numbersto ensure the traceability of each indicator to avoid the potential for manipulation across the distribution chain. As well as being effective for large shipments, Timestrip® PLUS are small light and cost effective enough to be used at the carton or single unit level. Using them at multiple points within a shipment or container can isolate unacceptable temperature pockets. Data loggers provide a full history of temperature from the time of activation. Timestrip® PLUS records how long a product has been above its threshold temperature (up to the maximum printed on the scale - usually 8 or 12 cumulative hours) but cannot tell you when the breach or breaches occurred. Timestrip® PLUS is most often used to monitor and validate the “last-mile” of a cold chain or other temperature environment, in other words, when the product is close to its eventual use. In some cases data loggers and Timestrip® PLUS indicators may be used in complementary ways to help monitor temperatures.
How does Timestrip® PLUS work?
A blue dye housed in a blister is held adjacent to a micro-porous membrane. Upon squeezing the activation button the liquid dye comes out of the blister and into contact with the membrane. If the temperature of the product is below the stated ‘STOP’ temperature, the  blue dye changes state to solid form, and it is unable to move through the membrane. If the temperature rises to or above the threshold temperature, the dye changes to liquid form and moves at a precise rate through the membrane. Its progress is irreversible and the distance it travels through the viewing window indicates the cumulative time the indicator has been exposed to the threshold temperature or above.  Once activated, Timestrip® PLUS will keep monitoring temperature for days, weeks or months, depending on your needs. During that time it will record how long any temperature breaches last. Here is an example. An 8°C Timestrip® PLUS was chosen to monitor a shipment which would take 3 weeks to arrive. When the shipment arrived, the indicator showed 4 hours of 8°C breach. This breach could have happened in one long event or from a series of shorter breach events across the 3 weeks. The 8°C Timestrip® PLUS could have indicated up to 8 hours of temperature breaches during that 3 weeks.
Why do Timestrip® PLUS have a ‘START’ and a ‘STOP’ threshold temperature ?
The melting point of a solid is the temperature at which it changes state from solid to liquid. The freezing point (or crystallization point) is the temperature at which a liquid changes to a solid. For certain substances the melting and freezing point are not the same and the freezing point is lower than the melt point. This behaviour is called hysteresis. At the STOP point (freezing point) the dye can’t move. At the melt point the dye moves and indicates a threshold breach.
Do I need to pre-condition indicators prior to activation?
No. Unlike some other threshold temperature products, Timestrip® PLUS does not require pre-conditioning. You need to activate above the product’s threshold temperature, as you cannot squeeze the dye out of the blister if it is in solid form. Immediately after activation, stop the progress of the dye by placing the indicator below its STOP temperature. You can adhere the Timestrip immediately to a product or carrying card which is below the STOP temperature. Alternatively place the activated indicator in an environment much colder than the STOP temperature for a short period of time.
Any special storage requirements before activation?
No, unlike some other threshold temperature products, Timestrip® PLUS can be stored inert at ambient temperatures and only activated when needed.
What is the shelf-life of Timestrip® PLUS?
Most Timestrip® PLUS products are provided with a shelf life of 2 years from shipping from our premises. Some formulations may be provided with a shelf-life of 2 years from date of manufacture. In all cases, an expiry date is provided for each batch of products supplied.
What if one of the indicators in my pack has got a blue activation window or there is blue in the run-out window, before I’ve pressed the activation button?
If stored under the correct conditions, there is very little risk of auto-activation, but occasionally, this can happen, and the built-in activation window lets you know it. If an indicator has auto-activated before use the activation window will already be showing blue and ON.  The blue liquid may also be showing against the time-markers in the run-out window.  If this happens, discard the indicator and select another.  There is no need to contact us, as we ship a few extra units per hundred anyway.
Can I customise the temperature threshold if you don’t make one that I need? 
We have a wide range, but if none of our products suit your needs we can investigate a new threshold temperature. There is a cost for this development service and not all temperatures are possible.  Please contact us for more information.
Can you customize Timestrip® PLUS?
For a minimum order value of 50,000 units we can make a customised Timestrip ® PLUS. There is a set up and per unit premium for this service dependent on the specifications required.  Graphic customisation can include changing the scale on the run-out window to different time markers and using customer logos and colours.  It can also include hiding the progress of the blue dye so the end user just sees when a maximum elapsed time of temperature abuse has been reached.
Can Timestrip Plus indicate if a temperature has fallen below a certain point?
Timestrip Plus™ can only show ascending temperature excursions. We have other products that do this type of descending temperature indication.
How accurate are Timestrip® PLUS?
+/- 1 ̊C for the temperature component and 15% for the time component under isothermal conditions. The progress of the blue dye across the time-markers is calibrated to a temperature of 2 ̊C above the stated threshold temperature. For example, the time markers for Timestrip® PLUS 12 ̊C are calibrated to a temperature of 14 ̊C. When the product breaches its threshold temperature and is held at a constant temperature of 14 ̊C (i.e. isotherm), the blue liquid will reach the 1 hour print mark within 1 hour (+/- 15% in time). If the breach is at a much higher temperature than the stated threshold temperature, the indicator dye becomes thinner and will run faster.
What can they be used on?
Anything where elevated temperatures are an issue. Common applications are frozen or chilled foods, medicines, vaccines, blood products and adhesives.
Can you customize for us?
We have a growing range of standard products that meet most cold chain requirements. As a general rule, if you require more than 50,000 units, we can customize the print, and in many cases, even the melt temperature, although we have an extensive existing range. There is a premium for this service. We can also quote on custom carrier cards and backing labels, if you need to provide instructions, add other languages, or a form to provide a permanent record.
What is the accuracy of the hour marks?
Every Timestrip Plus™ product is calibrated to a temperature of 2˚C above its stated threshold temperature. For example, Timestrip Plus™ 12˚C is calibrated to a temperature of 14˚C. When the product breaches its threshold temperature and is held at a constant temperature(i.e. isotherm) of 14˚ C, it will reach the 1 Hour print mark within 1 Hr (+/- 15% in time).
What is the maximum run-time Timestrip® PLUS range can offer?
The maximum run-time varies between hours to days dependent on the product and its application. Note that the run-time is only referring to the time above its breach temperature.  Timestrip® PLUS can remain active and vigilant for long periods of time (up to a year after activated) if the run out window has not completely filled in.
Why is there an activation window and a runout window?
The activation window gives confidence that the product is armed. The breach/run-out window is separate so that it clearly indicates a breach of the temperature threshold and the cumulative elapsed time of the breach.
What happens at elevated temperatures?
Due to the nature of liquids, higher temperatures reduce the viscosity of the liquid dye in Timestrip® PLUS. The correlated result is faster/shorter run-times (the progressing blue dye will reach each printed time-mark sooner than intended). So, if an 8°C/46°F indicator is exposed to 25°C/77°F for a consistent period then the blue dye will progress more quickly through the membrane than if it was exposed to 10°C/50°F for a consistent period. Timestrip Plus 10C GraphThis graph shows the run-time acceleration of a 10°C/50°F Timestrip PLUS at different elevated temperatures. The y-axis represents the actual run-time of the liquid dye at different temperatures, and is expressed as a percentage of the specified run-out time at an isotherm of 12°C/54°F. So, at an isothermal temperature of 12°C, the liquid dye will reach each time-marker (1, 2, 4, 8, hours etc) within these times +/-15% in time. However, if for example the product is exposed to an isotherm of 21°C/70°F the dye will reach each time marker within only 77% of the intended run-time. In other words, it will reach the;
  • 1 hour time-marker within approximately 46 minutes (77% of 1 hour)
  • 2 hour time-marker within approximately 1.32 hours and so on.
At a less extreme temperature elevation, say 15°C/59°F the blue dye will reach each time-marker at 91% of the intended time.
How are Timestrip® PLUS products evaluated for their time accuracy?
Timestrip®  PLUS are polymeric multi-layer indicators. They are based on spontaneous lateral wetting by a blue liquid inside a porous substrate and not a chemical reaction. Each production batch (7000 – 8000 products) undergoes strict quality control tests to validate its time accuracy. This is conducted via a computer vision software (TSCV) which analyses scanned photos of seven randomly-selected products from each batch (roughly 0.1% of the population). The photos are taken at different elapsed times and the tested products are placed at their designated temperature through the entire test period. The software automatically analyses the lateral progress and the elapsed time of each product tested and the data is presented numerically and graphically in a specific file which is labelled by batch.  This data is translated into a final release report which is attached to the outgoing product batches.  
What are your Acceptable Quality Limits (AQL’s)?
The Accepted Failure Rate is based on ANSI/ASQC Z1.4 (formally MIL-STD-105E) Level II Normal Inspection. Packs are over shipped by 2-3 units per 100 to cover this AQL. Central to this process are tests against defined specifications for; how quickly the dye progresses through the membrane, environment sensitivity (high heat and vacuum tests to check resilience to harsh conditions during shipping) and also the accuracy of the threshold melting point. A full pack of release reports is provided with each shipment. Further details are available on request.
Is the liquid safe?
Yes.  Please see the product MSDS on our website for further information. We only use food-grade oils and non-toxic colourants in our formulation. In the unlikely event that the liquid leaks from the indicator and comes into contact with skin, simply wash with soap and water. If the liquid comes into contact with eyes, rinse immediately with plenty of water and seek medical advice.

Timestrip® PLUS Duo

What is Duo?
Timestrip® PLUS Duo puts two temperature threshold indicators side by side into one handy label format. The indicator on the left shows if temperatures have breached the cold chain threshold of 10°C/50°F and for how long, with time markers for 3, 8 or 14 days. The indicator on the right shows if temperatures have breached an extreme of 34°C/93°F and for how long, with one time marker for 3 hours. Duo has been engineered to comply with World Health Organisation recommended monitoring requirements for certain vaccines. That is why it combines a threshold indicator of 10°C/50°F with 3, 8, and 14 day time markers and a 34°C/93°F indicator showing 3 hours of breach. However, there is nothing to prevent Duo being used to monitor other products if these time markers and threshold temperatures are suitable. It is also possible to manufacture Dual threshold indicators for other temperature thresholds. (See FAQ on customising Duo).
Why does Timestrip give away 1 or 2 free products with every pack of 100?
Because we like our customers! You can use these free products for testing, training, validation, or just to save money. In the unlikely case any got damaged along the way or someone just wanted to try one, there is no need to get in touch, although we're always happy to hear from our customers. Personally, we think that all companies should give stuff away for free!
Can Timestrips be used in any direction / orientation?
Yes.  Orientation has no impact on the way it works.
How does Duo work?
A blue dye housed in a blister is held adjacent to a micro-porous membrane. Upon squeezing the activation button the liquid dye comes out of the blister and into contact with the membrane. If the temperature of the product is below the stated ‘STOP’ temperature, the blue dye changes state to solid form, and it is unable to move through the membrane. If the temperature rises to or above the threshold temperature, the dye changes to liquid form and moves at a precise rate through the membrane. Its progress is irreversible and the distance it travels through the viewing window indicates the cumulative time the indicator has been exposed to the threshold temperature or above. The 10°C and 34°C threshold indicators use different liquid dyes which melt and solidify at different temperatures. The liquid dye in the 10°C blister has a STOP of 8°C/46°F and the liquid dye in the 34°C blister has a STOP of 30°C/86°F.
Do I need to condition Duo prior to activation?
No. Unlike some other threshold temperature products, Duo indicators do not require pre-conditioning. However, you need to activate above the highest threshold temperature, as you cannot squeeze the dye out of the blister if it is in solid form. The temperature of Duo needs to be raised to 35°C/95°F to be able to activate both indicators and then dropped to the lower of the two STOP temperatures (8°C/46°F) to stop the progress of both liquid dyes. The fastest way to do this is by placing Duo in an environment much colder than the STOP temperature (8°C/46°F) for a short period of time.
Any special storage requirements before activation?
No, unlike some other threshold temperature products, they can be held at ambient temperatures.
How accurate is Duo?
+/- 1˚C for each temperature component and +/- 15% for each time component. The run rate of the blue dye across the time markers is calibrated to a temperature of 2˚C above the stated threshold temperature. For example, the time markers for the 10˚C threshold indicator in Duo are calibrated to a temperature of 12˚C/54°F. If the vaccine being monitored breaches its threshold temperature and is held at a constant temperature (i.e. isotherm) of 12˚C, the blue mixture will reach the 3 day print mark within 3 days (+/- 15% in time).
What are your Acceptable Quality Limits?
The Accepted Failure Rate is based on ANSI/ASQC Z1.4 (formally MIL-STD-105E) Level II Normal Inspection. For Duo the AQL is 0.65%. Packs are over shipped by 2-3 units per 100 to cover this AQL. Duo indicators go through extensive quality checks before they are shipped. Central to this process are tests against defined specifications for; run-time accuracy (how quickly the dye progresses through the membrane), environment sensitivity (high heat and vacuum tests to check resilience to harsh conditions during shipping) and also the accuracy of the threshold melting point. A full pack of release reports is provided with each shipment. Further details are available on request.
Can Duo be customised for different time markers and temperature thresholds?
Yes. The temperature thresholds and time marker specifications can be adjusted. It also possible to change the graphic to incorporate customer colours and logos. All custom orders are subject to a minimum volume and the cost and specification will depend on what is required and feasible. Please contact us for more information.