Product FAQs

Because ATP is present in all active living organisms it is present in active microbial contamination in fuel systems. The Firefly has an enzyme called Luciferase that acts on a chemical called Luciferin in the presence of ATP and Oxygen to produce Oxyluciferin and LIGHT. The components of that reaction are harnessed in the HY-LiTE test pen. If the sample tested has ATP present in sufficient quantities, it will drive this reaction and produce LIGHT. The light is captured and read by the HY-LiTE luminometer giving a numerical reading as Relative Light Units (RLU) and hence an indication of the level of microbial contamination present in the fuel sample tested. Note; microorganisms are not the only source of ATP.

You will need a HY-LiTE Luminometer (light meter). Since readings from different manufacturers’ light meters are not in standard SI units but rather in “Relative Light Units,” it’s essential to use the Merck HY-LiTE Luminometer with HY-LiTE Test Pens. Light meters from other manufacturers should not be used, as they will give inconsistent readings.

Additionally, you will require a HY-LiTE Fuel Test Pen. There are two branded versions, both technically identical: the Merck HY-LITE Jet A1 Test Pen and the FQS Fuel Test Pen. Both are produced by Merck GmbH in Germany.

Yes, it can. You will also need a Luminometer, which can be operated using mains power or batteries. The Test Pens must be stored refrigerated (2-8°C), so only remove the number of pens needed for testing from refrigerated storage on the day of the test. The manufacturer advises allowing the Test Pens to reach ambient temperature by leaving them out for 30 minutes to 1 hour after removal from refrigeration before use.

The manufacturer permits a period of up to 3 weeks (to allow for transport) during which the pens can be stored at ambient temperature, defined as 23°C. Tests should be conducted within a temperature range of 5 to 35°C. Therefore, in hot climates, the ambient temperature might exceed the recommended testing range, necessitating a cooler location for testing.

Exposing the Test Pens to temperatures above the recommended storage conditions can reduce their shelf life. If this occurs, seek further assistance and provide details on the duration and temperatures of exposure.

The HY-LiTE® Test pens are sold in packs of 20 tests.

The ASTM method D7463 list the following fuel types:

• Fuel Oils (ASTM D396)
• Diesel Fuel (ASTM D975)
• Aviation Turbine Fuel (ASTM D1655)
• Gas Turbine Fuel (ASTM D2880)
• Diesel Fuel with up to 20% Biofuel content (D7647)

The frequency with which you test is dependent on the system being tested and the operational experience and perceived risk.  Recommended practice is to start monitoring at a higher frequency than required for routine testing to determine the risk of contamination.  Once a good track record is established the frequency of monitoring can be relaxed.

Example: Typically, a low risk fuel storage facility might monitor fuel storage tanks annually after an initial monthly to quarterly screening for 1 year.  High risk facilities would maintain a monthly monitoring program.

The HY-LiTE® Fuel test is suitable for detecting microbes in aircraft tanks that are well aerated. These tanks typically have conditions conducive to microbial growth.

In contrast, fuel storage tanks may contain bottom waters that can persist and become stagnant. In such environments, ‘anaerobic’ Sulphate Reducing Bacteria (SRB) can thrive. To detect SRB and assess the associated risk of corrosion, the Sig Sulphide test is recommended.

The HY-LiTE® Fuel test is a standard ASTM test method ASTM D7463.  The test is listed in the Aircraft Maintenance Manuals of Boeing, Airbus and other leading aircraft OEMs.

The HY-LiTE® Fuel test was designed to detect ATP.  Not all indicators of microbial contamination contain ATP.  Spores of microbes or dormant microbes will contain very little ATP and thus may not be detected by ATP technology.  Because spores can sometimes be the only indicator of microbial contamination in fuel samples which contain no free or suspended water it may not detect contamination under these circumstances.

HY-LiTE® works effectively with a wide range of petroleum products and associated water and is approved by major OEMs and widely adopted.  It is quick and easy to use, and more economical than laboratory tests.

HY-LiTE® is fully quantitative, indicating the severity of contamination rather than just the presence with “go, no-go” tests. It detects Hormoconis resinae, other moulds, yeasts, and bacteria.

According to the instructions, gloves can be used when handling the fuel sample, but they should not be used when handling the test pen. Certain glove materials can increase the risk of building up an electrostatic charge that could potentially damage the sensitive Luminometer. Therefore, do not use gloves when handling either the test pen or the Luminometer.

The manufacturer recommends using a HDPE bottle or equivalent for storage. Glass bottles may cause the capture solution to separate into numerous individual droplets, preventing them from coalescing into larger droplets that can be easily recovered.

Because the HY-LiTE® test detects ATP rather than living microbes, after a biocide treatment, the ATP level in a system may actually increase due to the release from dead microbes. Therefore, immediately following a biocide treatment, ATP tests may be susceptible to false positive results.

There is little or no ATP in spores; therefore, HY-LiTE® will not detect spores.

Why are Spores Important?

Spores are important because detecting spores is sometimes the only indication of microbial contamination within an aircraft tank.

Spores are produced by many different moulds and in vast quantities, they are usually much smaller than the actual microbes themselves and tend to be hydrophobic (water hating).  They are repelled by water but are freely dispersible in liquid fuels, this means that whilst the microbes themselves tend to proliferate and grow in any free water pockets in fuel system their spores are liberated into the fuel and disperse throughout it. In fuel tanks where isolated pockets of water may be present (which can be a long way from the drain points of the tank), spores which disperse and survive readily in fuel permit reliable detection of contamination by methods which can detect spores, even when no water is present in the sample.

No, it must be stored refrigerated at 2-8°C.

No, the recommended storage conditions are refrigerated at 2-8°C.

The contents of the HY-LiTE® test pen are non hazardous and should be disposed of in accordance with local waste regulations.

The shelf life of the test is approximately 1 year from date of manufacture. Because of the time taken between manufacturer and Quality Control release (which varies) the manufacturers do not advise the production or cure date, the expiry date is printed on the product.

Therefore, it is impossible to calculate the percentage remaining shelf life. The expiry date and batch number of the available tests is advised in advance of an order, and we only proceed when it is accepted

The HY-LiTE® Luminometer is classified as: Optical Analysis Instrument: Instruments and apparatus for physical or chemical analysis, using UV, visible or IR optical radiations. HS CODE 90.27.50.00.

The Harmonized System (HS) is a standardized numerical method of classifying traded products. The HS assigns specific six-digit codes for varying classifications and commodities. Countries are allowed to add longer codes to the first six digits for further classification. It is used by countries around the world to uniformly identify and describe products for purposes such as assessing duties and gathering statistics

The HY-LiTE® Test Pens are classified as: Prepared diagnostic or laboratory reagents whether or not on a backing, whether or not put up in the form of kits HS Code : 38.22.19.00.

The Harmonized System (HS) is a standardized numerical method of classifying traded products. The HS assigns specific six-digit codes for varying classifications and commodities. Countries are allowed to add longer codes to the first six digits for further classification. It is used by countries around the world to uniformly identify and describe products for purposes such as assessing duties and gathering statistics.