Identifying damp walls and avoiding mould

When old buildings are restored, this is done with the best intentions. The restoration is carried out in order to correct defective heat insulation and to avoid the increased energy costs caused by this. This usually involves installing new windows. While this solves the problem of the heat insulation, modern windows seal so well that the necessary air exchange is hindered. The consequence: The air humidity increases, forming the basis for the feared mould growth on walls and ceilings.   How does mould develop?   Mould spores, the seeds of the mould fungus, are everywhere. In order to grow, they need – in addition to nutrients such as dust, plaster, wallpaper or wood – above all water. If, for instance, water has penetrated into the living quarters due to a burst pipe, or if the indoor air has been too damp over several days, mould spores find ideal living conditions. The more humid the air, the better the mould can grow. The causes can be constructional defects, incorrectly implemented restoration or insufficient heating and ventilation, for example. In addition to the damage to health caused by mould, the building substance is also permanently damaged. Because of this, mould needs to be identified and eliminated in time.       The relevant measurement parameters In order to detect moisture damage, the following measurement parameters must be recorded:

Parameter	Indicates
Air temperature	…heating, ventilation and comfort in rooms.
Air humidity	…mould damage, and important indicator in technical building drying. Air humidity indicates how much water vapour is present in the air.
Material temperature	…the surface temperature of the material, and thus cold bridges, i.e. at which points heat is being drawn away from the material, allowing it to cool.
Material moisture	…the water content in mineral building materials. Measurements both at the surface (non-intrusive), as well as measurements in the material using an equilibrium humidity measurement (intrusive), are possible.

Isolating the causes   Once mould is in the building, the tenant initially supposes that the damp is coming from the outside. Many legal battles have ensued from the question of who is responsible for mould damage. It is very difficult to determine who or what has caused mould: the inhabitants or defective building construction? This is where modern measurement technology comes in. Contractors, experts and assessors usually have such measuring instruments in use, and can carry out in-depth research into causes within a very short time.

Measuring instruments for research into tenantrelated causes	Measuring instruments for research into construction-related causes
Air thermometers e.g. testo 610	Surface (contact) thermometers e.g. testo 905
Humidity measuring instruments e.g. testo 625	Infrared thermometers e.g. testo 830
Multi-function measuring instruments e.g. testo 635	Material moisture measring instruments, e.g. for stone and wood e.g. testo 616
Data loggers e.g. testo 175 H1	Thermal imagers e.g. testo 875

Detection of mould damage caused by tenants   The following measuring instruments are suitable: testo 610 for contractors in heating and sanitation Measurement of humidity and temperature in living quarters, bathrooms and new buildings   testo 610 is very small and handy, and can be carried with you conveniently at any time. testo 610 is simply held up in the room, and reliably, very accurately and at the touch of a button records the air humidity, temperature and dew point.       testo 625 for HVAC technology in buildings, quality assurance and production   Monitoring ambient indoor conditions testo 625 measures air humidity, temperature and dewpoint. In inaccessible points such as corners at ceiling height, the measurement values can be transferred wirelessly over great distances by the wireless module to the measuring instrument.       testo 635 for HVAC technology in buildings Testing of building substance and climatic conditions in and on buildings testo 635 measures air humidity, temperature, material moisture and U-value. The user can store the measurement results in the instrument, and later analyze and document them using the PC software. This makes uninterrupted documentary proof possible.       testo 175 H1 for use in industrial areas Long-term monitoring of air quality and indoor climate   testo 175 H1 continuously records temperature and humidity values and shows the dewpoint in the display. This allows the indoor climate to be monitored over a long period, underlining the necessity for a systematic exchange of air.       Detection of construction-related mould damage   The following measuring instruments are suitable:   testo 905-T2 for contractors in heating and sanitation   Contact measurement for the determination of surface temperature on radiators or heating systems testo 905-T2 adapts itself perfectly even to rough surfaces, achieving a high level of measurement accuracy. This allows the temperature on the surface of a wall, radiator, on valves or connections in a heatings system, to be measured quickly.       testo 830 for contractors in heating, sanitation and air conditioning Non-contact determination of surface temperature   testo 830 measures the surface temperatures of walls, ceilings and floors using infrared technology. This allows points which are too cold, at which humidity could precipitate, to be determined and if necessary countermeasures taken.       testo 616 for contractors in heating and sanitation Monitoring material moisture in building materials, e.g. after water damage   testo 616 measures material moisture non-intrusively using a contact probe in wood, screed, cement and concrete at a depth of up to 5 cm. The instrument simplifies the work of anyone who must observe the drying processes of floors, walls and surfaces as well as moisture damage.       testo 875 for the building trade and for energy consultation Identification of construction deficits on buildings   The thermal imager testo 875 shows deficits in materials and components, such as cold bridges, insufficient air-tightness, cracks in the brickwork or leaks, directly in the thermal image in the imager display. In the humidity mode, mould-risk areas are even shown up in red.     When the cause is incorrect heating or ventilation   Mould growth is in fact rarely caused by constructional deficits. The cause is more often the living habits of the tenants, for example incorrect or insufficient heating and ventilation of the living quarters. Because the humidity comes from the living quarters themselves, caused by the people, who automatically give off humidity to their surroundings. In colder places such as windows, this humidity leads to condensation, also referred to as “sweating”. For this reason, it must be extracted. In a four-person household, between 8 and 15 litres of water daily are given off into the ambient air in the form of vapour. The warmer the room, the more water can be absorbed by the air. If this water vapour now meets colder air, a part condenses back to water, which then precipitates, especially in colder areas such as corners of rooms, behind furniture and on outer walls. Heating the living room in the winter, and leaving lesser used rooms such as bedrooms or bathrooms cool does not save heating costs. It actually increases them more than if the complete apartment were to be continually heated. The higher the temperature difference between the rooms, the greater the danger that condensation can precipitate on critical areas. In addition to this, damp wall conduct heat energy more quickly to the outside. The result is mould fungus and mildew.     Humidity caused in living quarters daily: Cause Humidity in litres Humans sweating/breathing approx. 1.0 Cooking 0.5 – 1.0 Showering/bathing per person 0.5 – 1.0 Drying laundry – spin-dried 1.0 – 1.5 Drying laundry – dripping wet 2.0 – 3.5 Houseplants 0.5 – 1.0     Correct heating and ventilation   Observing a few simple heating and ventilation rules in the end not only prevents the development of mould in your apartment, it saves heating costs, protects the environment and ensures your own personal well-being.   Correct ventilation:  

• Ventilate intensively several times a day with windows and doors open wide.
• No long-term ventilation with windows only ajar, as this cools the brickwork too much.
• Turn down radiators and/or thermostats.
• Ventilate intensively immediately after cooking or showering.
• Do not place furniture directly against outer walls, but pull them a few centimetres away.
• The warmer the outside temperature, the longer the need for ventilation. Ventilate for a quarter of an hour on warmer days (over 12 °C), three minutes suffice on days with continuous temperatures below freezing.

    Correct heating:

• Ensure as uniform a temperature as possible in all rooms.
• Radiators must be freely accessible in order for the heat to be able to spread unhindered.
• Close blinds and curtains at night in order to avoid heat loss.
• Do not overheat the apartment. One degree Celcius of room temperature causes approximately 6% higher energy costs.
• Never switch heating off completely, even during longer absences. The rooms would otherwise cool down too much.

Professional room climate measurements – Deciding how to choose the right measuring instrument

Optimised measuring chains increase the efficiency of working procedures

Precise room and building climate measurements are challenging and require the compilation, analysis and documentation of a wide range of parameters. Thus, instruments which support the efficient processing and management of relevant data make the work of plant constructors, experts, consultants or service providers in the field of ventilation and air conditioning considerably easier. The following article illustrates the possibilities resulting from the current state of the art.

The range of technical instruments available on the market for measuring room climate reflects the wide range of requirements in this field. Depending on the intended application, different accuracy tolerances and features are of significance. However, anyone who regularly uses measuring instruments as part of his/her professional activities should not only be concerned about the required or prescribed measuring accuracy. In day-to-day work, aspects such as convenience of use, the capabilities for efficient further processing of the measurement data or the robustness of the technology under building site conditions are also of crucial importance.

Entry-level instruments for standard tasks 
Making a decision as to which instrument to purchase for simple measuring tasks is relatively easy. Here are a few practical examples: An HVAC expert wishes to check the insulation work on a heating system using non-contact temperature measurement. Or he is scanning the walls for the coldest points, in order to make the house owner aware of the mould problem. The common factor in such applications is that the measuring accuracy required is regarded as rather average. Moreover, there is no need to spend a lot of time and effort preparing documentation, which is an essential component of more demanding measuring tasks. Here entry-level instruments are normally sufficient for the controlled ventilation of living spaces, for example, and are available within the correspondingly low price brackets.

Climate measurement technology for complex requirements 
More stringent demands are placed on professional climate analysis instruments. Various measurement parameters need to be determined, sometimes under extremely variable conditions. For the flow velocity there are measuring probes specifically for ventilation ducts, outlets and for checking comfort level conditions in the workplace. Add to this temperature, humidity, pressure and also CO2 concentration measurements. These measuring tasks are not only carried out when installing and commissioning ventilation and air conditioning systems, they are also required during regular maintenance and inspections. Moreover, there is a wide range of analyses intended to rectify any lack of comfort, whether it be draughts, uncomfortable temperatures or tiredness as a result of high CO2 concentrations. Sometimes extremely complex measurements are required here, and these may extend over periods of several hours or days and include the evaluation of all climatic values acting upon the individuals concerned. Both newcomers to the industry and experts merely looking to brush up their knowledge can acquire the appropriate expertise and learn how to apply it in practice, through training sessions and seminars, such as those offered by Testo AG from Lenzkirch – a leading manufacturer of portable and stationary measuring technology.

Numerous standards are applied when carrying out the measurements, such as ensuring that the degrees of turbulence are determined at ankle, chest and head height for optimum analysis of the draught effect on a person in the room. Huge amounts of data are always recorded and processed in climate measurements of this kind, in order, among other things, to be able to recognise temporary disruptions – such as the opening of doors or windows – in the data records and take them into account accordingly. There are also standards for measurements in ventilation channels which, for example, prescribe a mean calculation for the flow profile. Consequently, these kinds of measuring tasks are usually carried out by highly-qualified specialists such as skilled tradesmen, technicians, engineers and experts. Although most standards are advisory only, a growing number of customers deem it important for measurements to be standards-compliant, and this entails spending more time and effort on documentation. Therefore, greater convenience in using measuring instruments and efficient work processes are just as important to users as having the capabilities for efficient further processing and for managing huge amounts of data.

Advantages of digital probe technology 
One development which brings considerable advantages with it, in particular for demanding measuring tasks in air conditioning and ventilation systems, is digital probe technology. Up to now, analogue measuring signals have been transmitted from the probes to the evaluation unit – that is, the handheld instrument – and converted into digital signals there for further processing. This signal processing, however, is subject to system-related uncertainties, the cause of which is mostly to be found in the interface between the handheld instrument and the probe. In digital technology, the probe itself produces a digital value, which is transmitted to the measuring instrument with no loss of information and totally error-free. The metrological intelligence is within the actual probe, while the handheld instrument serves as a display unit with different functions for saving and processing the data.
A further advantage of this technology is the fact that the user only needs to send the relevant probe into the calibration laboratory for the calibration that is required periodically; there is no longer any need to send in the complete system. Meanwhile the other probes can continue to be used with the handheld instrument.

Workflow optimisation measures 
In addition to the digital probe technology, modern measuring instruments – such as the newly developed VAC measuring instrument testo 480 – also have further innovative features for a high degree of user convenience and to efficiently evaluate, process and manage large amounts of data. Instead of navigating through the menus with cursor keys, here a so-called trackpad – similar to those found in Notebooks – facilitates the input by means of a touch-sensitive sensor surface. At the same time the multiple function of keys has been done away with, making operation of the handheld instrument much faster, simpler and more efficient.

Guided programs, which for example guarantee standards-compliant grid measurement on a VAC system in accordance with EN 12599, support the measuring process itself. There is also the option of configuring the reading display individually, thus creating a display and evaluation tailored to personal preferences. Archives, similar in structure to Windows Explorer, can be built up in the handheld instrument, enabling measurement data to be assigned to individual customers simply and directly. The colour display tops off the instrument's equipment, guaranteeing a high degree of user convenience.

The software shipped with the measuring instrument should also make data management and processing much simpler. Ideally, the complete data tree can be transmitted from the handheld instrument to the PC for further processing. Subsequently, professional protocols can be created on the computer based on previously stored templates. Here measuring locations, date, time, the recorded values, and if necessary also the logo of the service provider can be integrated quickly and easily. The possibility of transmitting data via a USB connection as well as by means of an SD card guarantees a high degree of flexibility. Thus, the air conditioning engineer can, for example, give the measurement results to a colleague to evaluate in the office and keep another appointment himself. Instrument and measurement data may therefore be used independently of one another.

Decision-making criteria for professional VAC measuring instruments 
Finally, the above instrument features collectively contribute to optimising the entire measurement chain, which ranges from preparing the measurement to recording the measurement parameters, and extends right up to creating the protocol. Most notably, the evaluations can be carried out using innovative measuring technology in a way that saves both time and money. This increases the efficiency of working procedures for all users, whether we're talking about a plant constructor, someone who provides air conditioning systems maintenance, an expert or consultant, or even an employee in the Facility Management Department of an industrial company or someone who runs an office block.

Thus, it is quite clear that solely comparing prices and measuring accuracies is not sufficient to select a professional VAC measuring instrument. In fact, the organisational support and the software provided ought also be put to the test. An ideal scenario is where the measurement data can be managed efficiently and recorded in compliance with the standards. The results must be able to be evaluated and configured individually to customer requirements. In this context efficiency means added value, because ultimately the customer is paying for the measurement protocol.

Info boxes:

Standards relevant to air conditioning measurement technology

VDI 2083-3         Clean room technology
VDI 6022            Hygiene requirements for VAC systems

EN 12599           Test procedures and measurement methods for handing over ventilation and air conditioning systems
EN 13779           Basic principles for planning, construction and operation for ventilation in non-residential buildings
ISO 7726            Ambient climate, instruments and methods for measurement

ISO 7243            Climate measurements at the workplace in the industrial sector
ISO 7730            Method for predicting human thermal sensation

DIN 18017          Ventilation of bathrooms and toilets, external windows with fans (Part 3)
DIN 33403-3      Climate at the workplace

Images:

Precise room and building climate measurements are challenging and require various measurement parameters to be established, sometimes under extremely variable conditions.

In the case of comfort level measurement at the workplace, temperature and flow velocity, and hence the degree of turbulence, are measured at ankle, chest and head height over a prolonged period of time, in order to be able to analyse the draught effect on a person in the room.

Digital probe technology transfers the measured values to the handheld instrument securely and reliably, guarantees a zero-error display thanks to the automatic elimination of deviations, and automatically sends notification when the next calibration is due to be carried out.

In digital probe technology there is no longer any need to send in the complete system for the calibration, just the relevant probe. Meanwhile the other probes can continue to be used with the handheld instrument.

In the case of modern measuring instruments such as the testo 480, the so-called trackpad, a clear archive structure which can be individually configured, and a colour display, among other things, all ensure a high degree of user convenience.

The software shipped with the measuring instrument should enable measurement protocols to be created quickly and easily, and to be configured in a manner that is tailored to the customer. The possibility of transmitting data via a USB connection as well as by means of an SD card also guarantees a high degree of flexibility.

Courtesy: All images: Testo AG
For more info, write to info@testoindia.com or visit www.testo.com/en-IN.

Detect CO reliably, identify malfunctions and avoid danger with CO Monitor

Carbon monoxide (CO) Detection gas is formed from the combination of a carbon atom with an oxygen atom. Not only flammable, it is also very hazardous since it is very toxic and odorless. It cannot sustain life and is produced, among other things, from incomplete combustion due to lack of oxygen. It can therefore cause domestic accidents if heating systems are poorly maintained. It is produced on a large scale in industry, in combination with hydrogen, by reforming hydrocarbons, generally natural gas. It is used in large quantities to produce various intermediary organic chemicals, such as acetic acids, isocyanates, formic acid, and also certain polymers such as polycarbonates and polyketones.

The current Occupational Safety and Health Administration (OSHA) permissible exposure limit (PEL) for carbon monoxide is 50 parts per million (ppm) parts of air (55 milligrams per cubic meter (mg/m(3)) as an 8-hour time-weighted average (TWA) concentration.

CO is the most common gas, which is detected for leakage, in all sorts of industries. Leakages from combustion devices like boilers, gas turbines, furnaces, heaters, incinerators, and from gas pipelines, and vessels, are detected using handheld, and fixed gas detection systems.

Testo 317-3 is one of the commonly used gas detectors in the industry. Its important to identify and stop a CO leakage at the earliest, and hence, fast and accurate detection of the leaked gas is of primary importance.  Testo 317-3 was developed to detect and measure CO gas absolutely reliably, and in case of danger to provide warning without delay.
 The testo 317-3 is absolutely insensitive to temperature fluctuations as well as humidity, and identifies malfunctions on a burner quickly and securely. It reports just as reliably when dangerous CO concentrations form in pellet stores - optically as well as audibly. You can evaluate the danger quickly and precisely thanks to the ppm display.
CO2 Measurement, Humidity Measurement, co measurement