Great to see everyone at the 2014 ISM in Grindelwald!
Control of Temperature and Humidity in Hospitals
Temperature and relative humidity affects the airborne survival of viruses, bacteria and fungi. Thus environmental control in hospitals is important because of infectious disease transmission from the aerosol or airborne infection.
Environmental exposure is a common hazard for all such organisms (whether viruses, bacteria or fungi) during this journey between hosts. Factors such as temperature, humidity (both relative and absolute), sunlight (ultraviolet light) exposure and even atmospheric pollutants can all act to inactivate free-floating, airborne infectious organisms.
Maintaining hospital premises at a certain temperature and a certain relative humidity (%rh), likely to reduce the airborne survival and therefore transmission of influenza virus. Temperature and RH settings in different parts of a hospital differ slightly between summer and winter. In summer, the recommended room temperatures range from 23°C-27°C in the ER (emergency room), including in-patient and out-patient areas, as well as X-ray and treatment rooms and offices. The corresponding recommended RH is fairly constant throughout the hospital, between 50- 60%rh. In winter, the recommended temperatures are generally slightly lower, ranging from 20°C in some in-patient and out-patient areas, as well as offices, up to 24°C -26°C in in-patient and out-patient areas.
The recommendations for the newborn baby and the hydrotherapy treatment rooms are higher at 27°C –28°C. Again, the corresponding recommended range of RH is fairly constant, but slightly lower than for summer, ranging from 40%rh -50%rh, but up to 55%rh–60%rh for more critical areas, such as operating theatres and recovery, the intensive care unit and childbirth/delivery suites.
Temperature is one of the most important factors affecting virus survival, as it can affect the state of viral proteins and the virus genome. Virus survival decreases progressively at 20.5°C –24°C then < 30°C temperatures. This relationship with temperature held throughout humidity range of 23%rh- 81%rh.
Facts & figures:RH (expressed in percentage) describes the amount of water vapor held in the air at a specific temperature at any time, relative to the maximum amount of water vapor that air at that temperature could possibly hold.
At higher temperatures, air can hold more water vapor, and the relationship is roughly exponential—air at high temperatures can hold much more water vapor than air at lower temperatures.
Why do we need to measure relative humidity?
Virus: The survival of viruses and other infectious agents depends partially on levels of RH. At a temperature of 21°C, influenza survival is lowest at a mid-range 40%rh–60%rh. It is also important to note that temperature and RH will always interact to affect the survival of airborne viruses in aerosols.
At High temperatures < 30°C and at high RH < 50%rh may reduce the survival of airborne influenza virus.
Bacteria : For bacteria, the effect of carbon monoxide (CO), enhanced the death rate at less than 25%rh, but protects the bacteria at higher RH ~ 90%rh.
Temperatures above about 24°C appear to universally decrease airborne bacterial survival.
Fungi: Ventilation systems controlling Temperature and Humidity have a significant effect on indoor levels of airborne fungi, with air-handling units reducing, but natural ventilation and fan-coil units increasing the indoor concentrations of airborne fungi.
Dehumidification as well as HEPA filtration can be used to improve indoor air quality.
Different airborne infectious agents (i.e. viruses, bacteria and fungi) will have differing conditions under which they may be optimally suppressed; it will need to be decided which airborne pathogen poses the most risk to patients and staff alike in hospitals.
Thus, in reducing infectious disease transmission specific environmental control of temperature and humidity is vital for hospitals and healthcare premises.
Rotronic can offering a complete system for hospital measurement applications: a proven system that enables healthcare facilities to control and monitor their conditions and remain in conformance with internal or regulatory guidelines.
With the combination of both analogue outputs, controlling the air-conditioning, and digital outputs, linked up to the Rotronic HW4 monitoring software, end users have a clear overview of conditions.Dr. Jeremy Wingate
Thorne and Derrick have written a great blog post on the importance of quality measurement and control in cheese manufacturing (a key industry for Rotronic sensors due to their reliance to the high humidity conditions in cheese maturing!)
Check out the post here…
Thorne and Derrick are national distributors and worldwide exporters of process & mechanical equipment.
Would you like us to share your blog posts on measurement or humidity? Please contact us!Dr Jeremy Wingate
Bread – The stuff of life!
Most of us have a never ending choice of the most delicious breads, cakes and pastries to please both the palate and the eyes. We have become so used to this diverse range of bread and baked products, but do you how bread originally came into existence?
The interesting history of what is now called the “staff of life”, bread, and the making of it, started in comparatively recent times.
At the very beginning of recorded history there was the discovery of fire making and thus along with light, heat could be generated. Then it was found that different grasses and their seeds could be prepared for nourishment.
Later, with the combination of grain, water and heat, it was possible to prepare a kind of dense broth. Hot stones were covered with this broth or the broth was roasted on embers and “hey presto” the first unsoured flat bread was created. This ability to prepare stable food radically changed the eating habits and lifestyles of our early ancestors. They progressed from being hunters to settlers.
Facts & figures:
- Records show that as early as 2600-2100 B.C. bread was baked by Egyptians, who it is believed had learned the skill from the Babylonians.
- On average, every American consumes around 53 lb (24 kg) of bread per year.
- The “pocket” in pita bread is made by steam. The steam puffs up the dough and, as the bread cools and flattens, a pocket is left in the middle.
- US Farmers receive just 5 cents (or less) for each loaf of bread sold.
Why the need to measure humidity?
The production of baked goods such as bread, cakes, biscuits and pastries requires a number of processing steps in which humidity and temperature play an important role.
After mixing, it is typical to divide the dough into pieces and allow it to rest for a few minutes so that the gluten network in the dough can relax allowing easier moulding, which is the next step.
If at that stage, the temperature is too hot the dough will be too sticky and cannot be easily processed further, if too cold the dough can become damaged during moulding which leads to holes forming in the bread. If the humidity level prior to the moulding process was too low a skin of dry dough can form on the dough surface. This makes it harder for the dough to increase its volume during the next
process step called proving.
Proving is the professional term for the final dough-rise step before baking, where 90% of the bread volume is achieved. To achieve consistently good dough rising results special chambers are used. These chambers can maintain the ideal environment for the yeast to grow. Depending on the yeast and flour used, temperatures between 38…42°C and humidity levels between 70…80%rh are considered ideal.
In summary, the use of quality ingredients and careful handling throughout the various stages of production will not result in a quality product unless the dough temperature, and the temperature and humidity of the bakery are carefully regulated. Modern day bakeries use custom ventilation systems that are controlled by precision humidity and temperature sensors.
So once again the behavior of the humble water molecule is to blame! In this case for the stricken faces of The Great British Bake Off contestants as they stress about the quality of their crust and whether the dough will be cooked through to perfection!
Rotronic is pleased to announce the introduction of its smallest ever temperature and humidity logger. The HL-1D measures only 90 x 60 x 23 mm, is well specified with good accuracy, durable and has high ingress protection against dust and water (IP67). HW4-Lite validated software for programming, data download and analysis is included. The logger is available now at a competitive, inexpensive price.
The Rotronic HL-1D logger is very suitable for monitoring and recording conditions for a wide range of applications across all industries, in commerce and for research organisations. The compact logger is particularly suitable for monitoring high value products of all types during transportation to ensure that quality is maintained.
The significant features of the HL-1D inexpensive logger include:
• High measurement accuracy of 3 %rh and 0.3 °C
• Slim, compact and durable. High ingress protection rating of IP67
• Clear LC display with configurable visual alarms
• Large data recording capacity: 32,000 data points
• Ranges: -20…70 °C, 0…100 %rh. Logging interval from 30 s
• Min / Max / Average statistical function on logger display
• Package includes HW4-Lite validated PC software with data analysis
• Three year battery life (with five minute logging interval)
• FDA 21CFR Part 11 / GAMP5 conformity
• Temperature only logger available (product code TL-1D)
HL-1D / TL-1D Logger Technical Datasheet – click here
Contact us now for logger pricing and additional information
The future is very encouraging for wind power. The technology is growing exponentially due to the current power crisis and the ongoing discussions about nuclear power plants. Wind turbines are becoming more efficient and are able to produce increased electricity capacity given the same factors.
Converting wind power into electrical power:
A wind turbine converts the kinetic energy of wind into rotational mechanical energy. This energy is directly converted, by a generator, into electrical energy. Large wind turbines as shown in the picture, typically have a generator installed on top of the tower. Commonly, there is also a gear box to adapt the speed. Various sensors for wind speed, humidity and temperature measurement are placed inside and outside to monitor the climate. A controller unit analyses the data and adjusts the yaw and pitch drives to the correct positions. See the schematic below.
The formula for wind power density:
W = d x A2 x V3 x C where :
d: defines the density of the air. Typically it’s 1.225 Kg/m3 This is a value which can vary depending on air pressure, temperature and humidity.
A2: defines the diameter of the turbine blades. This value is quite effective with its squared relationship. The larger a wind turbine is the more energy can be harnessed.
V3: defines the velocity of the wind. The wind speed is the most effective value with its cubed relationship.
In reality, the wind is never the same speed and a wind turbine is only efficient at certain wind speeds. Usually 10 mph (16 km/h) or greater is most effective. At high wind speed the wind turbine can break. The efficiency is therefore held to a constant of around 10 mph.
C: defines the constant which is normally 0.5 for metric
values. This is actually a combination of two or more constants depending on the specific variables and the system of units that is used.
Why measure the local climate?
To forecast the power of the wind over a few hours or days is not an easy task.
Wind farms can extend over miles of land or offshore areas where the climate and the wind speed can vary substantially, especially in hilly areas. Positioning towers only slightly to the left or right can make a significant difference because the wind velocity can be increased due to the topography. Therefore, wind mapping has to be performed in order to determine if a location is correct for the wind farm. Such wind maps are usually done with Doppler radars which are equipped with stationary temperature and humidity sensors. These sensors improve the overall accuracy.
Once wind mapping has been carried out over different seasons, wind turbine positions can be determined. Each turbine will be equipped with sensors for wind direction and speed, temperature and humidity. Using all these parameters, the turbine characteristics plus the weather forecast, a power prediction can be made using complex mathematics.
The final power value will be calculated in “watts” which will be supplied into power grids, (see schematic on the right). Electricity for many houses or factories can be powered by the green energy.
Why measure inside a wind turbine?
Wind farms are normally installed in areas with harsh environments where strong winds are common. Salty air, high humidity and condensation are daily issues for wind turbines.
Normal ventilation is not sufficient to ensure continuous operation. The inside climate has to be monitored and dehumidified by desiccant to protect the electrical components against short circuits and the machinery against corrosion. These measurements are required to ensure continuous operation and reduce maintenance costs.
What solutions can Rotronic offer?
Rotronic offers sensors with exceptional accuracy and a wide range of products for meteorological applications and for monitoring internal conditions.
Low sensor drift and long-term stability are perfect in wind energy applications where reduced maintenance reduces operational costs.
The wide range of networking possibilities including RS-485, USB, LAN and probe extension cables up to 100 m allows measurements in remote or hard to reach places. Validated Rotronic HW4 software makes it easy to analyse the data or it can be exported into MS Excel for reporting and further processing.
The ability to calibrate accurately using humidity standards and portable generators on site ensures continued sensor performance!
Comments or queries? Please do get in touch!
Rotronic have prepared a new White Paper on the subject of how modern digital probes and instrumentation are enabling new methods of field calibration. Download below…
Over the years there has been a rapid increase in large stand-alone data centres housing computer systems, hosting cloud computing servers and supporting telecommunications equipment. These are crucial for every company for IT operations around the world.
It is paramount for manufacturers of information technology equipment (ITE) to increase computing capability and improve computing efficiency. With an influx of data centers required to house large numbers of servers, they have become significant power consumers. All the stakeholders including ITE manufacturers, physical infrastructure manufacturers, data centers designers and operators have been focusing on reducing power consumption from the non-computing part of the overall power load: one major cost is the cooling infrastructure that supports the ITE.
Too much or too little Humidity can make one uncomfortable. Similarly, computer hardware does not like these extreme conditions any more than we do. With too much humidity, condensation can occur and with too little humidity, static electricity can occur: both can have a significant impact and can cause damage to computers and equipment in data centers.
It is therefore essential to maintain and control ideal environmental conditions, with precise humidity and temperature measurement, thus increasing energy efficiency whilst reducing energy costs in Data Centers. ASHRAE Thermal Guidelines for Data Processing Environments has helped create a framework for the industry to follow and better understand the implications of ITE cooling component.
Rotronic’s high precision, fast responding and long-term stability temperature and humidity sensors are regularly specified for monitoring and controlling conditions in data centres.
Why measure temperature and humidity?
Maintaining temperature and humidity levels in the data center can reduce unplanned downtime caused by environmental conditions and can save companies thousands or even millions of dollars per year. A recent whitepaper from The Green Grid (“Updated Air-Side Free Cooling Maps: The Impact of ASHRAE 2011 Allowable Ranges”) discusses the new ASHRAE recommended and allowable ranges in the context of free cooling.
The humidity varies to some extent with temperature, however, in a data center, the absolute humidity should never fall below 0.006 g/kg, nor should it ever exceed 0.011 g/kg.
Maintaining temperature range between 20° to 24°C is optimal for system reliability. This temperature range provides a safe buffer for equipment to operate in the event of air conditioning or HVAC equipment failure while making it easier to maintain a safe relative humidity level. In general ITE should not be operated in a data center where the ambient room temperature has exceeded 30°C. Maintaining ambient relative humidity levels between 45% and 55% is recommended.
Additionally, data centre managers need to be alerted to change in temperature and humidity levels.
Rotronic temperature and humidity probes with suitable transmitters or loggers are most suitable for monitoring & controlling conditions in data centres due to their high precision and fast response with long-term stability.
With Rotronic HW4 Software a separate monitoring system can be implemented. This enables data center managers to view measured values and automatically save the measured data. Alarm via email and SMS, with report printout allow data integrity guaranteed at all times.
Dr Jeremy Wingate
Last week Rotronic launched their latest small compact temperature and/or humidity data logger!
With the Friday off work myself and a friend thought how better to test the impressive little logger than slinging it in a pack and carrying it up through sun, fog, snow and rain on an audacious weekend attempt to climb the 4478m Matterhorn in the beautiful Swiss Alps (I confess my friend could not care less about the logger aspect but was certainly up for the climb).
With no time for acclimatization, the climb would be grueling enough without carrying additional instruments, but thankfully the HL-1D is very compact and light. It has 3 year battery life, can store 32,000 readings and has high measurement accuracy of ± 3.0% RH and ± 0.3 °C. Of course the logger is designed more for monitoring office and work spaces, transportation of products, production and storage environments, still we though it wise to push it to its limits!
Due to very poor conditions on the mountain we planned to overnight in a small hut at 4000m. So with our packs loaded we set off from the 2000m high gondola station above the beautiful village of Zermatt. But first ensured we were well fueled with ‘Apfel Strudel’ and coffee!
The climb itself started at 3000m and the temperature quickly began to drop as we gained altitude. At nearly 4000m the temperature dropped rapidly and clouds came in (shown by a rapid increase in the humidity). Luckily the Solvay Hut at 4004m provided welcome shelter and a ‘comfortable’ 3°C temperature (much warmer inside our sleeping bags).
The morning showed that the cold temperatures and thick cloud had turned to more heavy snow fall, making any further progress even harder. The fresh snow combined with the debilitating effects of altitude sickness meant that we (wisely) decided to head straight down (this was just a quick weekend getaway after all).
The decent was challenging and navigation difficult. Snow fall was consistent most of the day and topped off by a steady shower of rain as we made our final walk back down to the gondola station (you can see the logger showing 100%rh as the top pocket of my bag becomes saturated in the down pour).
Back in Zermatt and we quickly find shelter to dry off and find a good spot for a celebratory beer and hearty Swiss meal.
What of our little logger? It provides a great record of the trip. Values safely recorded through the freezing temperatures and soaking rain.
Full trace of the logger can be found below; click on the image for more detail.
If you would like more info on the latest compact logger click here or for any other measurement queries please do not hesitate to contact us!
Dr. Jeremy Wingate
There has been a rapid increase in large stand-alone data centres housing computer systems, hosting cloud computing servers and supporting telecommunications equipment, they are crucial for company IT operations around the world. Data centres must be extremely reliable and secure; many are wholly remote facilities.
Air conditioning is essential to maintain temperature and humidity levels within tight defined tolerances, thus ensuring the longest possible service life of the installed hardware.
Precise temperature and humidity measurement with fast reacting sensors is an absolute requirement. This increases energy efficiency whilst reducing energy costs. Additionally, data centre managers need to be alerted to even a small change in temperature and humidity levels. A separate monitoring system with networked alarms using fast reacting temperature and humidity sensors is installed.
Rotronic ‘standard’ HC2-S interchangeable temperature and humidity sensors are regularly specified for monitoring & controlling conditions in data centres due to their high precision and fast response with long-term stability. Used with a HygroFlex5 measurement transmitter analogue (scalable) or digital outputs are available exactly as required for interface with control systems. The loop can be validated electrically in minutes saving a significant amount of time. Probes can be exchanged rapidly when service work or periodic calibration checks are required.
Contact Rotronic for full product information
Tel: 01293 571000 Email: firstname.lastname@example.org