Saturday, September 26, 2015

Duct Cleaning Cuts Allergies

Occasionally I have a "guest speaker" provide the weekly article. This week, Gary Arena provides a some insight into the benefits of duct cleaning. Enjoy.

Allergies can be a serious problem for someone’s overall health. The high concentration of pollen has been at an all-time high this summer, and overall allergies are increasing each year. Sensitivities to mold, mildew, dust and dirt can make everyday life a struggle. When a home air adaption is supplying air that contains these allergens, life can be quite miserable.

Benefits of Air Duct Cleaning and HVAC Restoration:
By removing this containment from a home air adaption, the effect is greatly reduced. Clean, healthy, circulating air is a must for those highly sensitive people. It is not unusual for a person to realize immediate relief upon completing a cleaning of a home heating, ventilating, and air conditioning adaption.
Here are the top 9 triggers that contribute to asthma attacks and allergy symptoms:
1. Dust Mites
2. Mold
3. Second-Hand Smoke
4. Cockroaches and Pests
5. Pet Dander and Hair
6. Wood Smoke (solid burning fuels)
7. Outdoor Air Pollution
8. Nitrogen Dioxide (from gas burning appliances and utilities)
9. Chemical Irritants

When dirt and debris are removed from ductwork, the fans and motors that power a furnace no longer need to work as hard to distribute air. Advising people to routinely get their air ducts serviced and inspected is important. Not only does this properly maintain a building, but it keeps the quality of indoor air as pure as possible!
Written by Gary Arena from DUCTZ of Greater Lancaster and York Cities. Gary is the owner of the professional air duct cleaning company in central PA and is proud to serve a locally and family-owned franchise.

Thursday, September 10, 2015

Managing Large Numbers of Lab Students

The easiest way to manage your lab is to have one lab instructor for every five students. I have actually taught lab classes where we had this ratio and it was a lot of fun. We were able to spend a lot of time with each student and we were able to do things you just can’t do with larger groups. So what if you have more like 20 students per lab instructor? It is still possible to give them a good lab experience, but a lot more planning and organizing will be required up front, and there will be things that are just not practical. One management technique is to split up large groups into smaller ones and schedule them at different times, effectively making several smaller lab classes. Of course this means you must spend more time than usual since you will be repeating the lab for each group. This may not be an option for everyone depending upon the number of instructors, students, lab equipment, and available lab time. For most of us, there will come a time when we have to work with larger groups in the lab.

A common technique is to have students work in groups. I try to avoid this if possible because it often means a couple of confident students do the work and the rest of the group watches and writes down the results. In group projects, you can see the 80/20 rule at work: 80% of the work is done by 20% of the people. However, this can be managed if you know it is going to occur. Ask every member of the group a question that requires an understanding of the process. If they know they are going to be asked to perform a task or answer a question, they will at least pay more attention to what is going on.  For example, if the group is measuring the superheat on an air conditioning system you might ask different students

What is superheat?
What measurements are required?
How did you arrive at the current superheat?
What readings are necessary to use the manufacturer’s superheat charging chart?
What does the system charging chart say the superheat should be?
Compare the manufacturer’s specification to the actual operating superheat?

Some skills are so important, every student must perform them for you individually. Lighting an oxyacetylene torch is one example. An issue with large groups is simply the amount of equipment and tools available. Most of us would be hard pressed to come up with 15 oxyacetylene torch sets so that every student could have their own. Besides, I really do NOT WANT to have more than three rookies working torches at the same time. Once when I had a class of 18 students who needed to learn to braze, I worried about how I was going to teach all of them to handle an oxyacetylene torch safely. What I did was to demonstrate, as I always do and then ask questions to see what people remembered. We then went back over the procedure, paying particular attention to things that I felt they had missed the first time. Finally, I lined them up and had each student turn on the tanks, set the regulators, light the torch, adjust the flame, shut off the flame, and shut down the torch leaving it ready for the next student. If they hesitated, they repeated the process. I noticed that the students got progressively better, which was odd because the most confident students had stepped forward first. When I remarked to one student on how quickly and confidently he performed the task he replied “I saw it done 10 times before I had to do it.” In other words, the students waiting in line learned through the experience of their fellow students. This made me feel less guilty about having everyone wait in line to work with me. This method works well for procedures that can be demonstrated in a few minutes such as lighting torches, soldering, brazing, or installing gauges. If the students use their time wisely and pay attention to what is going on they will learn by watching others and everyone leaves with an important skill they did not have the day before.

Sunday, September 6, 2015

Labor Day

As we celebrate this Labor Day I am reminded of the many Americans who don’t want a day off, they are looking for a day on. Your job provides you with more than the financial means to support yourself. For most of us, we are identified by our profession. One of the first things people ask when meeting is “what do you do?” Having regular earned income also gives us a way to be more in control of our destiny. With a predictable source of income, you can better manage your life. This is crucial for people wanting to improve their lot in life.

I truly believe all our political leaders want to help. We would all like for everyone seeking employment to find it. There have been many attempts by government at all levels to pass legislation that would stimulate the economy and create jobs. Many of these programs focus on training people for jobs of the future. The problem is that it is very difficult to accurately predict the future and create truly new jobs, particularly in new and emerging technologies. I believe we would have more success investing our time and money training people for jobs that already exist, particularly in fields where industry growth exceeds the available workforce. HVACR is one such industry.

Jobs are available now for skilled HVACR technicians. Money spent in technical education prepares students for real jobs that we know exist, not jobs that we wished exist. Further, if you want new emerging technologies – train folks for commercial refrigeration. Commercial refrigeration is undergoing a major transformation involving new energy-smart, earth-wise technologies.  So training people for a career in commercial refrigeration IS training for jobs of the future. The lack of qualified technicians is limiting HAVCR contractor’s growth, which limits the growth of the nation’s economy. Again, these job opportunities exist NOW.

Preparing people for a real job that pays real money makes them a contributing taxpayer. This means that the government gets the money back. Some HVACR students will be successful enough to start their own business. There are several in the Athens area who started as students at Athens Tech. One relatively small business with five employees can gross $1,000,000. That generates tax revenue of $150,000 at 15%. If those five employees are trained at Athens Tech, the cost of their training is less than one year’s tax revenue. Not all students will generate that kind of return, but even a student earning $12 an hour will likely pay back the cost of training in less than five years. For people who already have a job in HVACR, education makes them more productive and earns them more money. Increased productivity means a better bottom line for the government – more income to tax. It is not necessary to start new programs with new administrative costs; there are already programs and institutions in place with proven track records of training workers for skilled trades. All we have to do is support them.    

Monday, August 31, 2015

What Flavor is Your CO2 System?

If you work in any phase of refrigeration, you undoubtedly have heard about the emergence of CO2 refrigeration systems in commercial refrigeration. I had the pleasure of touring the HillPhoenix Refrigeration plant in Conyers today, and I was impressed by both the number and variety of CO2 systems they are currently building. They had Cascade systems, Trans-critical systems, Glycol systems and Booster Systems all using CO2. These are distinctly different approaches to working with CO2.

The transcritical has probably received the most press. It derives its name from the fact that the high side operates above the critical point while the low side operates below the critical point. The name indicates that the system operates on either side, or across, the critical point of the refrigerant. The critical point is the pressure and temperature at which the refrigerant can no longer condense to a liquid. So the “condenser” is really just a gas cooler. The refrigerant does not condense to a liquid until AFTER the pressure is dropped. The critical temperature of CO2 is 88°F, so any time the high side temperature rises above 88°F, the refrigerant will not condense. The pressures are bit higher than you might be used to – over 1200 psig, so not just any compressor and piping will do. However, in a way, the transcritical systems are a bit simpler than the other flavors.

Cascade systems use two complete refrigeration systems – one system’s job is really to cool the condenser of the other system. If you keep the CO2 cold enough, say 40°F, the pressures are not that high. However, to have a 40° condenser requires a system whose evaporator is in that same temperature range and whose condenser is at the normal operating temperature for an air cooled condenser. This system typically uses HFC refrigerant. So you have a heat exchanger and an HFC system to keep the CO2 system cool. This allows wider range of compressors because the CO2 compressors are not operating at 1200 psig. However, the system operating with the normal temperature condenser (80°F – 100°F) will have a refrigerant OTHER than CO2.

And then there are the booster systems. The booster systems incorporate both low and medium temperature racks into a single unit. The low temp CO2 compressors pump into the suction of the medium temp CO2 compressors, which operates at transcritical temperatures and pressures. This way the low temp compressors don’t have to be heavy duty transcritical compressors, just the medium temp compressors. The system uses only CO2, no HFC refrigerant is required, as in a cascade system.

There are also glycol systems, where the refrigeration system cools glycol, which is pumped through the store to the cases. This reduces the amount of refrigerant in the system and reduces leaks by reducing the amount of piping, fittings, and braze joints. What became apparent in my visit was that there are many ways to solve the same problem, and you can expect to see different solutions at different locations. It also is apparent that in commercial refrigeration, CO2 is here to stay and HFCs are on their way out.      

Monday, August 17, 2015

OSHA Updates Confined Space Safety Rules

Contractors who work in crawl spaces and attics may find the latest confined space regulations ... confining! Until recently, residential contractors rarely had to worry about confined space regulations. Now they will need to address confined space regulations on most jobs - both installation and service. OSHA just made changes to the confined spaces rules which will affect everyone that works in residential attics and crawl spaces. Considering that a large amount of residential HVAC equipment is installed in an attic or crawl space, these changes will affect residential HVAC contractors. A confined space is now defined as

  1.         Large enough to get your body in
  2.         Limited means for getting in and out
  3.         Not designed for continuous occupancy

The employer is responsible for providing a competent person to inspect all confined spaces before work begins. This person is looking for any other hazards which can make the confined space more dangerous, such as toxic fumes, low oxygen, electrical hazard, fall hazard, or extreme temperature. (Note this is only a partial list.) If the confined space has any additional hazards it becomes a permitted confined space. Workers can only enter a permitted confined space for the purposes listed on the permit under the conditions and restrictions listed on the permit. A hazard warning must be posted at the entry to a permitted confined space and a permit issued that lists all the details regarding work in that particular confined space. There must be an attendant posted outside a permitted confined space any time a worker is in the space. There are many more regulations. This is honestly only the tip of the iceberg. Suffice it to say, you want to avoid having to declare the confined space a permit required confined space. 

You are allowed to remove hazards to accomplish this. For example, a typical attic with no floor is a permitted confined space based on the fall hazard. If you put boards down for the workers to walk on you remove that hazard, and it no longer requires a permit. Similarly, an electrical hazard can be removed by turning off all power to the confined space. If a confined space has no additional hazards, then you can use what OSHA refers to as an alternate procedure. For this, the competent person must determine that no additional hazards exist, or that they have been removed. The space needs continual positive ventilation while work is being performed. However, the permit and the attendant are not required. Note that this still requires a competent person to inspect the pace BEFORE work begins.

Some logical questions come to mind, such as

Who is the competent person?
The competent person can be one or more of your employees who have been trained to recognize hazards in confined spaces and can use test equipment to test for oxygen level, combustible gasses, or toxic gasses. In the event of an incident, they will be asked to clearly tell OSHA what procedures they used identifying the risks involved with the space. 

Where do I get the permit?
For confined spaces requiring a permit, your company generates the permit – not some government agency. The purpose of the permit is to clearly communicate the conditions under which the space may be entered and who may enter.

When does this go into effect?
The new rules will start being enforced on October 2, 2015.

Where can I read more about this? (Trust me, you NEED to even if you don’t WANT to)

Monday, August 10, 2015

Legionnaires Cooling Tower Article

I just saw this article in the NEWS discussing Legionnaires and cooling towers - very good info. Since this ws the subject of my most recent post I thought I would share this important information.

Friday, August 7, 2015

Defeating Legionnaires Disease

Legionnaires disease is back in the news. It is caused by the legionella bacteria. The disease is most commonly spread by dirty cooling towers. The legionella bacteria grows in dirty tower water, and is transported to the surrounding area in the mist droplets leaving the tower. When someone breathes in water mist contaminated with legionella, they may contract a pneumonia that can kill people in a few days. 

The good news is that this is relatively easy to prevent by simply keeping the cooling towers clean.  Normal tower water maintenance will prevent the legionella from growing in the tower in the first place. If you have ever had a back yard wading pool for the kids, you know how quickly water left outside can develop slime – literally in a couple of days. Now think how quickly stuff can grow in water that is being heated, as in a cooling tower. Cooling towers need constant maintenance to stay clean. 

This can be done by testing the water weekly and adding chemicals as needed, or by using an automated chemical feed system. Even with an automated system, the water should be checked monthly to insure everything is working properly. Every building that uses a cooling tower should have someone on staff or contracted to keep an eye on the water condition. Some chemical salesmen will perform this service in exchange for buying all the chemicals from them. Obviously, the cost of their service is built into the price of the chemicals. In general, you want to maintain a slightly acidic ph to discourage calcium deposits and critter growth. 

Another reason to keep your cooling tower clean is that the same water circulating through the tower is also circulating through your condenser. A coating of green slime inside your condenser will insulate the condenser from the water passing through, reducing system efficiency. This translates into higher operating cost. You are not saving money by skipping cooling tower maintenance, you are spending it on increased system operating cost. Here are a few links with more details on cooling tower maintenance.