Chemours (Dupont) Buys ICOR International

I just got an email info blast from ICOR in which it states that ICOR is now a wholly owned subsidiary of Chemours. Tht surpised me, so I looked a littel further into it and found an article on :Cooling Post" dated April 8, 2018 which confrms that Chemours bought ICOR. Here is the link to the Cooling Post artcle
https://www.coolingpost.com/world-news/chemours-buys-refrigerant-supplier-icor/
Here is the link to the info blast that ICOR sent me.
http://www.icorinternational.com/images/C-11673RisksofLow-QualityRefrigerants-ChemoursBranding.pdf

Basically it is warning against cheap refrigerant from unknown sources. As always, if you stick with legitimate supply houses you are pretty safe. If you get it off the back of someone's truck at midnight in the parking lot behind the bar, well you might not be getting what you think you are getting. Even ordering over the internet is risky if you are are buying it from someone outside of the normal distribution chain. There is now counterfeit refrigerant out there, so just because the jog says Honeywell or Chemours does not mean that it really is from that manufacturer. Some of the counterfeit stuff has hydrocarbons in it and could be quite dangerous in a system that is not designed for explosive refrigerant.

Glove Cut Resistance Ratings

Did you know that gloves have ratings? When looking for a glove to protect your hands from cuts and scrapes you should get a pair that matches the required duty. There are actually two different glove ratings for cut resistance: ANSI/ISEA 105 and EN 388. In the United States we use ANSI/ISEA 105 which had a significant update in 2016.  There are nine levels, A1 – A9, with A9 being the most cut resistant. The gloves are tested by placing a fixed amount of pressure on a blade while moving it across the glove for a distance of 20 millimeters (roughly ¾ of an inch). The tool used is called a tomodynamometer which moves a razor blade slowly across the material being tested at a specified pressure for a specific length. The glove cut resistance levels are established based on the amount of pressure required to cut through the material. The Table below shows the nine levels in the ANSI system. You can see that the minimum recommended cut level for HVAC work is A4.

ANSI/ISEA 105 2016 Glove Cut Rating
Grade	Pressure Required to Cut Through	Recommended Use
A1	200-499 grams	General Purpose Material Handling
A2	500-999 grams	Packaging, paper handling
A3	1000 – 1499 grams	Handling construction materials
A4	1500 – 2199 grams	HVAC, duct work
A5	2200 – 2999 grams	HVAC, metal fabrication, metal stamping
A6	3000 – 3999 grams	HVAC, metal fabrication, metal stamping
A7	4000-4999 grams	HVAC, metal fabrication, glass manufacturing
A8	5000 – 5999 grams	HVAC, metal fabrication, glass manufacturing
A9	6000 or more grams	HVAC, metal fabrication, metal recycling

There is no requirement for glove manufacturers in the United States to test and label their gloves, so many gloves are sold without the cut rating. However, better manufacturers test and label their gloves. Look for gloves that have an ANSI/ISEA rating of at least A4 to protect your hands. To learn more, check out this page from Superior Glove Company.

Glove Rating Systems Explained

Flammable Refrigernats

I confess that I have always thought of flammability as an either or question: it either burns or it doesn’t. So the concept of different levels of flammability was a hard one for me to grasp. I wondered: what is the difference between 3,2, and 2L refrigerant designations? What follows is a somewhat lengthy discussion of what I learned.

First off,  found that it is not all that simple. There are several flammability characteristics that can be compared: lower flammability limit, upper flammability limit, auto ignition temperature, minimum ignition energy, heat of combustion, and flame velocity. The table at the bottom of the article shows these different specifications for a small selection of flammable refrigerants. Note that pressure and temperature also play a part. For the ASHRAE safety tests, a temperature of 140°F at atmospheric pressure is specified. You get different results when applying higher pressures and temperatures.

The original three classifications (1,2,3) were determined by the lower flammability limit and the heat of combustion. A refrigerant is classified as highly flammable, Class 3, if  either it requires 3.5% or less less by volume for a flammable mixture or it has a heat of combustion equal to or exceeding 19 kilojoules per gram. Note that EITHER condition will place it in class 3. Class 2 refrigerants require a concentration greater than 3.5% by volume to create a flammable mixture and they must have a heat of combustion less than 19 kilojoules per gram. Note that BOTH conditions must be met in order to be classified as class 2. Later, ASHRAE added a 2L category for refrigerants with burning velocities less than 10 centimeters per second. The table below summarizes the different flammability classifications.

Classification	Lower Flammability Limit % by volume	Heat of Combustion	Burning Velocity
1	Does not support combustion at atmospheric pressure
2L	Greater than 3.5%	Less than 19 kj/g	10 cm/s or less
2	Greater than 3.5%	Less than 19 kj/g	Greater than 10 cm/s
3	3.5% or less	19 kj/g or more	NA

Lower flammability limit (LFL) is the minimum percentage required in air to be combustible. For example propane (R290) has an LFL of 2.1% by volume while ammonia (R717) has an LFL of 15%. Notice that propane only requires 2.1% while ammonia requires 15%. So that is one difference – the amount that must build up before it can burn.

Upper flammability limit (UFL) describes the maximum concentration which will still burn. If the concentration of flammable vapors exceeds the UFL, it will not ignite. It is more difficult to draw a straight line comparison using the UFL. However, you can say that refrigerants whose LFL and UFL are closer together are generally a bit safer simply because the conditions dor a flammable mixture are less likely to occur.

Auto ignition temperature is the lowest temperature at which it spontaneously ignites in normal atmosphere without an external source of ignition. With the exception of 1234yf, the lower flammability refrigerants have higher auto ignition temperatures than the more flammable refrigerants.

Minimum ignition energy is a bit different than the auto ignition temperature. It is the minimum amount of energy required to ignite a flammable mixture, measured in megajoules. Note that in this case R1234yf stands out because the minimum ignition energy is so high compared to the other refrigerants. Also note that the class 2L refrigerants all have minimum ignition energy ratings in the hundreds of megajoules or higher while propane’s minimum ignition energy is a very small 0.25 megajoules. Basically, this means it takes a lot more energy to ignite the 2L refrigerants than a highly flammable refrigerant such as propane. Again, this means that the chance of having the right condition for combustion is much lower for class 2L refrigerants.

Heat of combustion is a measure of the amount of heat created when the refrigerant burns. Note that the class 2L and class 2 refrigerants have a heat of combustion in the single digits per gram while propane jumps to 46 kilojoules per gram. This means that the heat produced by combustion of a class 2L or class 2 refrigerant is far less than a class 3 refrigerant. Indeed, it would be possible for a class 2L refrigerant to burn and not ignite other nearby flammable materials.

Burning velocity is the characteristic which distinguishes 2 and 2L refrigerants. It is the speed with which the flame advances. Note that the 2L class refrigerants have a burning velocity in the single digits while 152a, a class 2 refrigerant, has a BV of 23 cm/sec. Propane’s burning velocity is twice that of 152a. The take home point here is that the flames from higher flammability refrigerants spread faster.

So wrapping it up, my general impression is that lower flammability refrigerants are less likely to burn in the first place and when they do burn, the flames are not as hot and do not spread as quickly as a high flammability refrigerant such as propane.

  

Refrigerant	R1234yf	R32	717 Ammonia	152a	290 Propane
Safety Group	A2L	A2L	B2L	A2	A3
Lower Flammability LImit	6.5%	14.4%	15%	3.9%	2.1%
Upper Flammability Limit	12.3%	33.3%	28%	16.9%	10%
Auto Ignition Temperature	405°C	648°C	651°C	440°C	455°C
Minimum Ignition Energy	5,000 – 10,000 mJ	30 – 100 mJ	100 – 300 mJ	0.38 mJ	0.25 mJ
Heat of Combustion	9.5 kJ/g	9 kJ/g	22.5 kJ/g	6.3 kJ/g	46.3 kj/g
Burning Velocity	1.5 cm/sec	6.7 cm/sec	7.2 cm/sec	23 cm/sec	46 cm/sec

CSST Gas Lines

If you use flexible gas connectors or CSST (corrugated stainless steel tubing) when hooking up the gas to a gas appliance, you need to make sure and do it safely. Flexible gas connectors are made of corrugated stainless steel and generally have no outer covering or protection. They are often used to connect a gas appliance to a rigid iron gas line. 

CSST, on the other hand, has an outer covering over the corrugated stainless steel, comes in large rolls, and is often used instead of black iron when piping gas lines. There are some installation practices for each of these products that need to be followed to avoid setting up a dangerous situation.

For flexible connectors, it is important that they not be used to go through walls, floors, or the unit cabinet. Iron pipe should pass through the unit cabinet to the gas valve. Contact with the metal side of the furnace cabinet can rub a hole in a flexible connector. Another reason for keeping flexible connectors out of the cabinet is the potential for loose electrical wires or connections to arc against the flexible connector and blow a hole in it. While this could also happen with black iron, there is far less likelihood of the arc blasting a hole in the iron. 

Flexible connectors can be used to make the final connection between the black iron leaving the furnace cabinet and the black iron piped into the furnace area. When using a flexible connector, the flared connectors are generally considered “unions.” Don’t forget to install a gas shutoff. Some flexible connectors are provided with a gas shutoff.

CSST is similar to flex connectors in construction with an outer layer of protective plastic. CSST can be pulled through interior walls, but metal nail protectors are required anywhere the CSST is inside the wall. CSST manufacturers make striker plates for this purpose. Protection needs to be approved by a listing agency, such as CSA or UL. Also, it is still best to use black iron to go into the furnace cabinet. The best practice is to penetrate exterior walls with black iron. If CSST is used to penetrate an exterior wall, protection is required.

One of the biggest safety concerns with both flexible connectors and CSST piping is properly grounding the gas piping system. There have been many instances where lightning strikes near a building have blown holes in CSST gas lines or connectors. The grounding is to avoid this. The most common practice is to connect a bonding ground wire to the rigid black iron pipe outside the house BEFORE the first CSST connection. This bonding ground is connected to the ground rod or run inside to the ground bus of the electrical panel.

Here are a couple of links for more information”

Grounding: http://www.csstsafety.com/CSST-solution.html

Installation: http://www.tracpipe.com/Technical/CSST_Installation_Instructions/  

Check Combustion Air

With the weather getting cooler, I thought that now would be a good time to talk about combustion air. Don’t forget to check for proper combustion air. Most codes provide detailed drawings illustrating where combustion air should come from and how much you need, but there are still many furnace installations that rely entirely on air from inside the building for combustion air. In days gone by this was often considered adequate so long as the furnace was located in a large enough space. In newer homes, combustion air should always be provided.

Most 90%  furnaces today can operate using sealed combustion. In the case of a sealed combustion furnace, the combustion air is being piped in from the outside. The combustion air is piped directly into the furnace. These are easy to spot, they have two pipes: one for combustion air and one for the vent. Also, their panels have no louvers for combustion air. 

Traditional furnaces get their combustion air from the space where they are installed. Combustion air enters through louvers in their panels.Since the furnace is drawing air from the space it is in, fresh combustion air must be supplied to the room to keep the process going. Failure to supply the correct amount of combustion air can lead to negative room pressure, vent spillage, poor combustion, and CO production. All these things together can be disastrous.

When a technician checks a furnace that does not have sealed combustion, one of the first things to look for is how the furnace receives combustion air. If the furnace is in a ventilated crawlspace or attic, the ventilation for those spaces provides the combustion air. However, even these can be a problem. A large furnace in a small crawl space may not have adequate combustion air if the crawl space vents are closed. I have also seen crawlspace vents clogged with debris, effectively reducing the combustion air.  

The most troublesome installations are furnaces located inside the house in a closet. They should have a combustion air vent near the floor and another near the ceiling. Someone asked me about a furnace installed in a closet off of a bathroom. When they turn on the bathroom vent fan, they can smell gas! Another story involved a fireplace and a furnace. When the furnace came on it sucked the smoke out of the fireplace into the room. These types of stories indicate that the furnace does not have adequate combustion air. 

What if there are no obvious combustion air vents? Sometimes the vents were never provided, other times they have been covered up. I have seen combustion air vents covered with tape or plastic. Undoubtedly, someone noticed cold air coming in the vent and “fixed” the problem – thereby creating a combustion air problem. Occasionally insulation covers the grille into the attic. Another problem is using the furnace closet for storage. This is dangerous in and of itself, but it can also cause combustion air problems if boxes are stacked in front of the combustion air grilles.  For details on combustion air requirements check your local code. Unit 53 Gas Furnace Installation in Fundamentals of HVACR, 3rd ed also has detailed drawings and specifications for the most common applications.  

Personal Gas Safety

Time for furnace tune-ups is here. Soon you will be taking the first no-heat calls of this heating season. No doubt you will be inspecting equipment for safety concerns that affect the customer. Don’t forget to pay attention to your own personal safety. Gas leaks, leaky vent systems, incorrect combustion, and lack of combustion air can all create immediate hazards to the service tech working on the system. There are pro-active steps you can take to stay safe while working on gas fired equipment.

Gas Leaks

If there are existing gas leaks it is possible that a combustible atmosphere exists in the space. Ideally, you want to check the air in the space for combustible gas before entering. You can use an electronic combustible gas detector for this. Many techs now use these to check for gas leaks, so you might already have the tool. Just turn it on and let it sample the air in the room as you enter. There are also personal detectors which you can wear to monitor the conditions wherever you are. If you do detect combustible gas in the room, do NOT turn on or off any electrical switches and leave the room. Shut off the gas outside and ventilate the room before continuing. You will have to turn the gas back on to find the leak, but you can ventilate the room and start with a safe atmosphere while you are doing it.

Carbon Monoxide

Negative room pressure, incorrect or leaky gas venting, and lack of combustion air can all contribute to a build-up of carbon monoxide in the room. You can’t smell or see carbon monoxide, so it is especially dangerous. Again, you should test the atmosphere in the room. There are electronic detectors made to check for carbon monoxide in the air, and some are made to wear to monitor the air continuously. If the monitor indicates a build-up of CO in the room, you should shut off the gas outside the room and ventilate the room. Once the room is cleared of CO you can start to look for the cause. Before turning the gas back on make sure to check for obvious things such as blocked combustion air intakes or compromised gas vents. After restarting the furnace you should check the flame color and test the flue for proper operation. Also be sure to check the flue gasses for CO.

Gas Ignition Problems

When observing a gas furnace light, you should never place your face directly in front of the furnace. If there is a delayed ignition or flame roll-out you can be inside the fire-ball. I have made that mistake. It was over before I knew what happened. For a second all I could see was yellow because my head was in the fireball that came out of the furnace. Luckily it just singed my eyebrows a bit and gave my face a slight burn similar to a sunburn. Afterwards I worked out what had happened: a leaky gas valve had allowed a build-up of gas prior to turning the furnace on. Had my face been off to the side I would not have been in the flames when they came out.

Don’t leave your personal safety to chance. 

Take steps to detect and avoid possible personal safety hazards. It is an inconvenience to the customer to have to call 911.

Sorting Out Refrigerant Flammability

Most techs know that ASHRAE Standard 34 originally established three categories of refrigerant flammability: 1,2, and 3. They ranged from 1 – nonflammable, to 3, highly flammable. Category 2 was listed as mildly flammable, or somewhat flammable. Then they added a new category – 2L – for an even lower category of still flammable refrigerant. I admit that I always found that a bit confusing. In my mind, it either burns or it doesn’t.  In order to get a better handle on this I have done some studying.

Two characteristics are used to differentiate category 1 and category 2 refrigerants: the lower flammability limit and the heat of combustion. The lower flammability limit is the lowest percentage concentration of gas in a gas-air mixture that will ignite. Concentrations lower than the lower flammability limit will not burn. Even highly combustible gasses such as gasoline have a lower flammability limit. Refrigerants with a lower flammability limit of 3.5% or less are considered class 3, highly flammable. For comparison the lower flammability limit of gasoline is 1.4%  and propane‘s is 2.1%. Another way for a refrigerant to be considered class 3 is for its heat of combustion to equal or exceed 19 million joules per kilogram. In general terms, it does not take very much class 3 refrigerant to burn and when it does it is very hot.

Class 2  refrigerants have a lower flammability limit greater than 3.5%. It requires more than 3.5% concentration in order to ignite. Class 2 refrigerants do not burn as hot as class 3 refrigerants: their heat of combustion is lower. The lower heat of combustion is important because that is what sets other things on fire. It is possible for a class 2 refrigerant to burn without burning up everything around it.

So where does the 2L come in? Flammability class 2L is really a subclass of 2. Refrigerants with a 2L designation have a burning velocity of 10 centimeters per second or slower. The burning velocity is how fast the flame travels. A burning velocity of 10 cm/s means that the flame will travel about 4 inches in a second. In contrast, the class 2 refrigerant HFC-152a  has a burning velocity of 23 cm/sec.  – a little more than twice as fast.  Propane, a class 3 refrigerant, has a flame velocity of 39 centimeters per second – 4 times as fast.

Why is this important? The flame velocity and heat of combustion are what determine whether or not an explosion can occur. Rapid burning and high heat of combustion expand the air and combustion gasses so rapidly that great pressure is created, blowing things apart. Class 2L refrigerant cannot burn fast enough or hot enough to blow anything up. In many cases, a burning class 2L refrigerant will not even catch other combustible things around it on fire.

To summarize:
Class 3 Refrigerants have a lower flammability ratio of 3.5% or lower and/or a heat of combustion equal to or greater than 19Mj/kg. They burn fast and hot.

Class 2 Refrigerants have a lower flammability ratio exceeding 3.5%. It takes more of them to burn and they do not burn as hot as class 3 refrigerants.

Sub-Class 2L Refrigerants in addition to a lower flammability ratio exceeding 3.5% also have a flame velocity of 10 cm/sec or less. They burn slowly and without releasing as much heat.

Class 1 Refrigerants do not burn.

Keep Your Cool

This week I am passing along a tip contributed by a reader, Mike Lilley. He keeps cool by wearing a cooling vest. After doing a little research I found three types of vests for sale: one that circulates air, some that use evaporation, and some that use phase change gel. For attic work I think we can rule out the air vest because it works by circulating ambient air through the vest. In dry heat the evaporative vests should work well, especially outside. However, in an attic in the southeast, I think their performance would not be enough to keep you cool. Mike said that the workers at his company use cooling vests with phase-change gel packs.

The gel packs are similar to the blue-ice packs you might use for your cooler, with one big difference. This gel freezes and melts at 58°F. Remember that the temperature of a substance stays the same as it changes state. This is an important concept in making air conditioning work. This gel stays at 58°F until all of it has melted, and 58° is comfortable, as opposed to keeping a 0°F gel pack next to your body. Further, you can freeze the removable gel packs in a refrigerator or in a cooler with ice. A couple of users commented that it is important to keep the packs flat during the freezing process. Otherwise, the hard, lumpy gel packs make the vest uncomfortable. Here is a link to learn more about these cooling vests. I must tell you that I have not personally used one – yet. But is certainly sounds like a cool idea.

Here are a few links to learn more about cooling vests.  
https://www.amazon.com/TECHKEWL-Phase-Change-Cooling-Vest/dp/B0002EWKTS
http://www.coolvest.com/
http://www.mycoolingstore.com/cooling-vest.html

CO Safety and the HVACR Tech

There is more to carbon monoxide safety than leaky furnace heat exchangers. Venting problems may actually cause more CO safety issues than leaky heat exchangers. I am not suggesting that you overlook the importance of checking furnace heat exchangers for leaks, but rather that you expand your CO safety horizons a bit. I want to talk about CO safety concerning the technician – you. A combustion appliance operating in an unsafe condition can spill vent gasses containing CO out into the room where it is operating. This can create a safety hazard for technicians going into that area to service the furnace. You should carry a CO detector that displays the CO level in the area you are working in. If the ambient CO goes above 50 ppm – you should leave. 50 ppm is the OSHA standard for the maximum allowable concentration for an 8 hour work day.

Ray Wohlfarth recently published an article in the October 2015 issue of Plumbing & Mechanical magazine in which he discusses a story of an electrician being overcome by CO fumes. The electrician was working in a mechanical room on something completely different than the boilers, but the boilers were in that room and not operating properly. When the electrician failed to report back to the school administration, the secretary was sent to see what was taking him. She found him passed out on the floor – ran and called 911 to get emergency medical help. This undoubtedly saved his life. Suppose that had been a service technician working on a furnace with nobody home? By the time someone found the tech – it would probably be too late.

Before you go to a big box store to get a home CO detector, consider that they are typically built to UL 2034 standards, which allows 15 minutes before alarming at levels above 400 ppm. This is just not fast enough in the case of high levels. The UL standard is weighted to prevent false alarms, but this also means that a UL listed device can fail to alarm at dangerous levels until it is really too late. Plus, typically these do not show what the CO level is. Kidde, a primary manufacturer of these types of CO monitors, points out that their devices are for continuous monitoring – not short term detection.

Single gas, battery operated CO detectors which display the CO level are available for $100 - $150. Alternately, you could use the CO setting on your combustion analyzer. If you don’t have a combustion analyzer, you could put that $150 you would normally spend on a single gas CO detector towards one of the lower cost $500 combustion analyzers. You will be doing both yourself and your customers a favor.

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)

 Final Ruling

Training Webinar Video

Enfocement Date 

OSHA Confined Space Page

How Does an Air Conditioner Cabinet Become Energized?

The last two weeks I have been talking about electrical safety. Specifically, discussing the electrical hazard of an energized system cabinet. This week I would like to discuss ways that the cabinet of a system can become energized. First, for a cabinet to have a voltage other than ground, the cabinet is either not grounded, or the ground has failed. Failure to properly ground a metal cabinet is the first condition that sets up the electrical hazard. But another mistake or failed component is required to actually energize the cabinet. Some are obvious – such as a loose energized wire touching the cabinet. Others are less obvious, such as a grounded electric motor. If a motor is grounded (not shorted or open) and the equipment cabinet in which the motor is mounted is not grounded, when the motor is energized the cabinet will also become energized. Motors can sometimes be grounded and still operate. So you touch an operating unit and get shocked. Another failure that can energize a cabinet is a broken or missing insulator on heat strips. Most heat strips have one side that is wired hot all the time. If the ceramic insulators break and allow the strips to contact the frame holding them, the cabinet can become energized.

A sneaky way for a cabinet to be energized is to wire a 110 volt device into a 230 volt unit using one leg and ground. Basically, current will be going through ground anytime the 110 volt device operates. This alone won’t cause an energized case. But if the ground between the unit and the panel breaks or just gets a bad connection, now there will be a voltage between the case and the actual ground – and the case will be energized. To avoid this, don’t wire 110 volt devices this way. You either need a separate neutral AND a cabinet ground (4 wires), or you need a 230 – 110 transformer. This is why newer electric dryers have 4 prong plugs: two for the 230 volt hot legs, one for neutral for the motor, and one for a cabinet ground.

So here are a few simple rules to help you avoid creating an electrical hazard:

1. All metal cabinets and pipes should be grounded
2. Ground wires should never be used as part of an operating circuit.
3. When equipment has both 230 volt and 110 volt loads, the equipment either requires a neutral wire AND a separate ground wire, or a 230 volt to 110 volt transformer.

Oxy-Acetylene Torch Safety

One of my e-buddies, Dave Christensen, suggested that I write about oxy-acetylene torches. He recently bought a new torch and confessed that he read the instructions before using it. In the instructions, he noticed that the regulator settings were different from the ones he had used for years. When we teach students to use torches in school, we typically teach them the regulator settings that work for the equipment we have. I am afraid we may not always make sure students understand that torch settings are not universal. The correct regulator setting depends upon the torch manufacturer, the tip size, and the application. Torch manufacturers typically provide these settings in the instructions.

There are a few guideposts that stay the same. For example, you NEVER, NEVER, NEVER set acetylene above 15 psi. In fact, I get nervous above 10. The reason is that acetylene is unstable at pressures above 15 psi and can explode. So how does it not explode in the acetylene cylinder at 250 psig? It is dissolved in acetone liquid which is stabilized in a porous core. That is why you should never transport or use acetylene cylinders on their side – it lets the liquid run out of the cylinder into the valve area. Also, you really don’t need the oxygen above 20 psig. Many tip charts have it about half that for most applications. However, the exact settings you should use are ... in the instructions!

Another common safety issue is leaving your regulators set and just opening and closing the tank valves when you want to use the torch. This is convenient and saves time, but it is dangerous. Regulators can fail because of the sudden bump in pressure. This can cause parts to fly and high pressure gas to stream down the hoses. The last thing you should do when shutting off your torch is to adjust the regulator T handles out counterclockwise until all the spring pressure is released. When the cylinder valves are opened they should be in this position. AFTER opening the cylinder valves you can adjust the regulators to he correct pressures.

When lighting the torch, you should light the acetylene first by itself and then bring in the oxygen. Opening both the acetylene and oxygen simultaneously can cause oxygen to flow into the acetylene hose and regulator if the oxygen pressure is higher than the acetylene pressure. This can create a very dangerous situation – a mixture of fuel and oxygen under pressure in the hose and regulator. The only place we want this type of combustible mixture is in the tip.  When shutting down, reverse the process. Close the oxygen first and then the acetylene.

Torch manufacturers have some very good training material available for free. Here are some links to some good training resources.

http://training.victortechnologies.com/

http://www.harrisproductsgroup.com/en/Products/Equipment.aspx

http://uniweld.com/en/uniweld-videos

Cut it Out!

The safest way to remove a refrigeration component is to cut it out, rather than de-brazing it. In the case of filter driers you don’t want to heat the drier and drive moisture and contaminants back into the system. With all components, there is the hazard of fire caused by vaporizing the refrigeration oil in the system. Heating the joint enough to render all the brazing material molten increases the temperature and pressure. When you pull the part loose, a stream of gasses comes out and is ignited by the torch flames and/or the red metal. Even if the refrigerant is non-flammable, the oil will burn. People have been seriously injured when large amounts of flaming oil discharged on them after de-brazing a refrigeration component. The most serious cases involved people de-brazing a system that was still fully charged. Accidentally cutting a line on a charged system would not be nearly as hazardous as de-brazing one.

In addition to the flame hazard of the oil, all fluorinated refrigerants create nasty, toxic fumes when exposed to flames even if they don’t burn. If you have ever gotten a strong snort of this stuff you know it is an experience to be avoided.

One more reason to be cautious now is the presence of so many refrigerant blends with small quantities of hydrocarbons in them. Although the quantity of hydrocarbons is small, the hydrocarbons can concentrate in the compressor oil when charged into a system with mineral oil. Even after recovery, there can still be volatile hydrocarbons in the compressor oil. You heat it to de-braze the compressor, and a flammable gas comes out when you pull the pipe loose. I have heard one story where the technician was de-brazing a compressor and was engulfed in a ball of flames for a short period of time after pulling the line out of the compressor. It was a brief flash fire that burned off his eyebrows and gave him a sunburn, nothing too serious – but definitely scary. The refrigerant was an R22 replacement rated A1/A1. Also, consider that with so many replacement refrigerants you really don’t know exactly what is in the system. Although the highly flammable R22 replacement refrigerants are illegal, they are widely available on the internet and they are sold to anyone with a credit card. Just on the off chance that the system you are working on was topped off with propane, you should avoid de-brazing. Make sure and purge the system with nitrogen before brazing the new compressor in. Not only will you avoid oxides inside the lines, you might also avoid fires in the area you are working in. I believe refrigerants with some degree of flammability will become more common. To be safe, we need to start treating all systems as if the refrigerant could burn. So the next time you have to remove a refrigeration component – CUT IT OUT!

Keep Outside Combustion Appliances Outside

Every winter I hear a few sad stories of people getting ill or dying because they decided to operate an outdoor combustion appliance inside their house. Most often, this occurs during a power outage. One example, someone decided to bring their charcoal barbeque grill inside the house to cook because it would also provide heat and they wouldn't have to stand out in the cold. They didn’t realize that burning charcoal creates lots of carbon monoxide. Their daughter got deathly ill, so they rushed her to the hospital. Fortunately, that got everyone out of the house and she recovered. Charcoal tells you right on the bag not to do that, but we don’t all read the instructions. You also hear about people running generators inside. Last year in Atlanta, a family died of carbon monoxide poisoning due to carbon monoxide from operating a generator in their basement overnight during a power outage. Gasoline engines should never be operated inside. A simple rule for staying safe is: if it is normally operated outside, keep it out there. Although there are probably many creative ways to use outdoor tools and appliances inside, there is usually a reason they are designed to be operated outside. I am sure most folks involved in HVACR already know this, but many of your friends and acquaintances may not. So do folks a favor, pass the word that charcoal grills, generators, and gasoline powered tools should stay OUTSIDE!  

Exploding Refrigeration Containers

Prices for HCFC 22 are finally rising to the levels that were expected this past summer. With the rise in refrigerant price will come increased interest in replacement refrigerants. For your safety as well as your customers safety, make sure you know where your refrigerant comes from. Avoid bargains from people you don’t know. This is not just about obeying the law, it is also about safety. Several container refrigeration systems have exploded after being charged with counterfeit R-134A. Container refrigeration is more difficult to patrol because the containers travel all over the world. Three articles discussing the accidents involving the mystery replacement refrigerant can found World Cargo News, ACHR News, Huffington Post.

Although flammable refrigerant s can be used safely, systems using flammable refrigerant use components designed for that use. Systems designed for flammable refrigerant also have limits on the amount of charge in the system and carry warnings regarding the flammability of their refrigerant. To stay safe, only use SNAP approved replacement refrigerants and only purchase refrigerant through the normal supply chain.