Question and Answer


  1. What is the correct name for an instrument like DewCheck?
  2. When is the best time to measure the climate parameters with the Dewcheck gauge and how many time should I measure during a working shift?
  3. Should I check the climate parameters as well when no work is in progress?
  4. How can I control the climate conditions with my dpm after working hours or during my absence?
  5. Why does my Dewcheck remains accurate and is guaranteed for 2 years while many electronic hygrometers need frequent recalibrations?
  6. Is it necessary to measure surface temperature in hard to reach spots? Should a separate probe be helpful?
  7. What makes Dewcheck dew point meter the best choice for use in the protective coating industry?
  8. Why is "Delta T" such an important parameter?
  9. Why is humidity so important?
  10. Do I need to measure climate when using waterborne coating?
  11. Can I measure other surfaces than steel with my Dewcheck dew point meter?
  12. Why is there a flash-light integrated in the Dewcheck dewpointmeter?
  13. A Dewcheck requires an investment which is higher than the relatively low-cost sling psychrometers and mechanical thermometer. Why should I pay this extra money?
  14. What is new about the DewCheck4 Series 2?
  15. Does DewCheck dewmeters come in different versions?
  16. Is a DewCheck waterproof?
  17. Will a DewCheck humidity sensor condensate when it is brought from a (very) cold environment into a warm environment?
  18. Will a condensed humidity sensor cause DewCheck malfunction?
  19. Could dust particles and pollution influence the DewCheck dewmeters sensors?
  1. What is the correct name for an instrument like DewCheck?
  2. Dewcheck has become a generic name for products that measure the relevant climate parameters for coating applications. Other wordings are: Dewmeter, Dewpointmeter or dew point meter in short dpm.

    top>>

  3. When is the best time to measure the climate parameters with the Dewcheck gauge and how many time should I measure during a working shift?
  4. Always follow the paint specifications if these prescribe the frequency of measurements. In case this topic is not included in the specifications the frequency of measurements should be decided using common sense. Climate parameters like the relative humidity and air-temperature and therefore also the dewpoint are changing continuously. Depending on the results of the Dewcheck gauge one could decide how often measurements should be taken. If the surface temperature is well above dewpoint on an early and shiny summer morning it is most likely no problems may be expected during the coming day if weather conditions remain stabile. On the contrary, if the surface temperature is just over 3°C above dewpoint at the end of the day and the air temperature is falling rapidly it is advised to increase the frequency of measurements. Keep in mind that the climate conditions are also important after the work is stopped. A wet coating or bare sandblasted steel will suffer from condensation as well.

    top>>

  5. Should I check the climate parameters as well when no work is in progress?
  6. This depends on the situation. When bare steel (open blast) is left behind at the end of a shift or working day it is critical to avoid condensation. Also when a freshly applied coating, that has not been cured properly, is left behind the climate parameters has to stay within their critical limits. Especially at night times, when ambient temperatures drop (negative) climate changes can be expected. Many clients such a certain defence departments and ship-owners now dictate climate registration throughout the entire coating process.

    top>>

  7. How can I control the climate conditions with my dpm after working hours or during my absence?
  8. DewCheck dewmeters have different data-logging options. A manual log option is build in but this is only useful when the instrument is in the hand of an operator. With optional Dewcheck Dock it is possible to fix the instrument with a set of integrated magnets against a steel object, also a magnetic surface probe is included. Configureted like this the instrument will log all climate data autonomous. Data can be downloaded to a PC for analysis or record keeping at the end of the job.

    top>>

  9. Why does my Dewcheck remains accurate and is guaranteed for 2 years while many electronic hygrometers need frequent recalibrations?
  10. The performance of each hygrometer depends mainly on the quality of the RH-sensing element. The Dewcheck dew point meter is equipped with a Rotronic® C-94 sensor. Almost 10 years of experience in producing dew point meters for coating applications has lead to this choice. This sensor from Switzerland has a reputation as one of the best sensor elements in the world. The Rotronic® C-94 sensor is especially developed for high end measuring applications in harsh industrial environments and for portable equipment. It is mend to remain accurate and stabile for year during continuous operation. Many hygrometer uses sensors that are originally designed for use in static applications like air-conditioners, wash dryers etc.. These sensors are to be used as indicators rather than for measuring applications. Although the cost price of a Rotronic® C-94 sensor is significantly higher than most other RH-sensors it has proven to be the only sensor element that could guarantee the Dewcheck dew point meter years of accurate measuring without the need for frequent recalibrations.

    top>>

  11. Is it necessary to measure surface temperature in hard to reach spots? Should a separate probe be helpful?
  12. Dewcheck dewpointmeters (dpm) are mainly used during the painting of large structures. Most of the times larger area's are being coated. The surface temperatures are being taken at specific spots which are considered to be representative for the whole area that will be coated at that moment. These specific spots are usually not chosen in hard to reach area's. Often inspectors need to climb ladders or scaffolding, a one handed gauge therefore comes in more handy that an instruments having a separate probes. When not in use the Dewcheck dew point meter can be safely stored in its special holster-case complete with belt-clip. Beside this a probe cable is sensitive and get easily damaged. Probe cables often get stuck.

    top>>

  13. What makes Dewcheck dew point meter the best choice for use in the protective coating industry?
  14. First of all the idea of developing a combination gauge to measure all specific climate parameters including Delta T specifically for the surface treatment industry was originated in our company. In 1992 TQC started comprehensive research after the needs of the specific customers group such as coating inspectors which lead to the first generation of Dewcheck climate gauges. The experience of producing and servicing dewmeters for such a long time has generated a wealth of experience and information that was used to create the latest model of Dewcheck gauges.

    • The gauge is a truly "one hand" operated gauge. No cables that can get stuck or damaged.
    • The instrument has been specifically developed for use in harsh environments. Electronics, sensors and housing are all extremely robust.
    • Due to the integrated filter at the RH-probe and its excellent recovery characteristics (100% recovery) after condensation of the RH-probe (or in rainy weather) the instruments is ideal for outdoor use. It is designed for use outdoors.
    • Large rubber keys and the ergonomically shaped housing makes is possible to use the instrument wearing gloves.
    • Illuminated display and the build-in flash light make the dew point meter (dpm) ideal in poorly lit situations.
    • The special designed holster case made of genuine leather protects the instrument when not in use.

    top>>

  15. Why is "Delta T" such an important parameter?
  16. Delta T is the surface temperature minus the dew point temperature. If a surface temperature drops below its surrounding dew point temperature condensation will occur immediately onto that surface. Condensation (moisture) can cause the following problems:

    • On sandblasted uncoated steel is will cause almost immediate flash rust (Condensation is hardly visible on rough blasted steel).
    • If a coating is applied onto steel with condensation the coating trap the moisture which can cause a poor adhesion, delaminating or other failures of the coating system.
    • Condensation on a just applied, uncured coating can create numerous problems varying from stains or gloss problems to delaminating of following layers etc..

    top>>

  17. Why is humidity so important?
  18. Each coating manufacturer will specify the humidity conditions that are required to perform a proper application of the coating. Some coatings (eg. Epoxies) may not be applied when the humidity is higher than eg. 70% or 80% while other coatings (moisture cure coatings) do require a humidity over a certain minimum level in order to achieve a perfect cure.

    top>>

  19. Do I need to measure climate when using waterborne coating?
  20. Yes! Especially with waterborne coating the humidity and temperature are very important. A low humidity will dry the coating too fast which makes a proper application impossible. A high humidity will cause the coating to stay wet and is will not cure. Too low temperatures , especially below freezing point, will destroy waterborne coatings.

    top>>

  21. Can I measure other surfaces than steel with my Dewcheck dew point meter?
  22. Yes! The Dewcheck surface probe can be used on any type of surface. Although the major field of application is within the steel protection industry such as the painting of ships, bridges, tanks and other steel constructions the dew point meter is also used for during painting works on concrete, brick, wood, plastic, non Ferro metals etc..

    top>>

  23. Why is there a flash-light integrated in the Dewcheck dewpointmeter?
  24. Dewcheck's are often used in confined spaces such as (ballast)tanks and cargo holds since climate conditions are unpredictable in the locations. An extra light can be a great help if the inspectors flash-light fails.

    top>>

  25. A Dewcheck requires an investment which is higher than the relatively low-cost sling psychrometers and mechanical thermometer. Why should I pay this extra money?
  26. There are various reasons:

    • Timesaving
    • Faster - while these devices take several minutes each to stabilize per measurement, the Dewcheck Dew Point Meter displays all 5 values (a Dataset) in a few seconds.
    • Ta - Air Temperature
    • Ts - Surface Temperature
    • RH - Relative Humidity
    • Td - Dew Point Temperature
    • Δ - the difference between surface and dew point temperatures

    • Easier to use
    • There is no need for counting revolutions per second in a timed interval using de-ionized water ,reading a "hard to read" glass thermometer (impossible in poorly lit situations), using a slide-rule calculator ,waiting minutes for a surface thermometer to stabilize and finally looking up values in a cross reference table.

    • Easier to handle
    • Truly one handed design with large back lighted display.

    • More accurate
    • Tighter tolerances on all values, less chance on human-errors and no miscalculations.

    • Robust
    • No fragile glass thermometers, sensitive bi-metallic thermometers but a robust piece of electronics in a strong compact package.

    • Versatile
    • Unlike a sling psychrometer, the Dewcheck Dew Point Meter (DPM) works well in cold environments and hot. The logging options increases its versatility even more.

    top>>

  27. What is new about the DewCheck4 Series 2?
  28. DewCheck 4 Series 2 is now standard supplied with a USB communication cable and the TQC Dewlog Analysis software. Firmware and hardware of the Series 2 have been renewed in order to enhance accuracy and long term stability.

    top>>

  29. Does DewCheck dewmeters come in different versions?
  30. No, with one instrument ALL climatic parameters that are necessary for a paint job can be measured. Each Dewcheck has full memory on board and USB connectivity. To use the instrument on site as a permanent dewpoint data logger, the special magnetic holder with probe needs to be bought.

    top>>

  31. Is a DewCheck waterproof?
  32. No, a DewCheck dewmeter (DPM) is not waterproof. A DewCheck dewpoint meter is typically used in situations where circumstances should be dry. When it rains there is no need to use an instrument. Some instruments claim to be equivalent to a certain IP class. Note that EQUIVALENT is different from COMPLIANT. Stating matters this way usually is not without reason.

    top>>

  33. Will a DewCheck humidity sensor condensate when it is brought from a (very) cold environment into a warm environment?
  34. The DewCheck humidity sensor is extremely thin and lightweight. Its body temperature will follow temperature changes very fast thus avoiding condensation in fast climate changes in 99% of the situations. Other dewmeters on the market use humidity sensors positioned directly on a printed circuit board. This increases the mass of the sensor and will slow down the acclimatisation of the sensor's body, often with condensation of the humidity sensor as a result.

    top>>

  35. Will a condensed humidity sensor cause DewCheck malfunction?
  36. No, if the rare occasion occurs that a DewCheck sensor condensates the moisture will evaporate within seconds and the instrument is ready-to-use. Accuracy is not influenced.

    Some other sensors used in the industry need quite some recovery time after condensation and often show some form of hysteresis. To regain accuracy and achieve correct measurements these sensors should be put into an extremely dry environment (below 20%RH) for a considerable time.

    top>>

  37. Could dust particles and pollution influence the DewCheck dewmeters sensors?
  38. Like any other sensitive instrument it is advised to keep the instrument as clean as possible. The dew point meter's humidity sensor is typically the most sensitive part. A thin white membrane protects this sensor. This is one of DewCheck's unique features. Other gauges have open sensors on which dust particles may adhere directly to the sensing element. In combination with the sensor condensating regularly dust will "bake" onto the sensor which on a longer term leads to drifting values. Even when an instrument is "Dustproof" its sensor needs to have contact with the air in order to take measurements.

    top>>

Deutsch English