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Refrigeration Technicians Best Tools

Refrigeration

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October 8, 2023

Essential Tools for Every Refrigeration Technician: A Comprehensive Review

Are you intrigued by the inner workings of refrigeration systems and the vital role they play in our everyday lives? Whether you’re an aspiring refrigeration technician or a seasoned pro, understanding the tools of the trade is essential.

In this comprehensive review, we delve into the top tools that every refrigeration mechanic should have in their arsenal. These tools are not mere conveniences; they are the very instruments that empower technicians to diagnose, repair, and maintain refrigeration systems efficiently and effectively.

1. Manifold Gauge Set: Refrigeration mechanics rely on manifold gauge sets to simultaneously measure high and low side pressures in refrigeration systems. These sets are like the eyes of the technician, providing critical insights into the system’s condition. By providing real-time data, refrigerant gauges are essential for diagnosing issues and ensuring optimal system performance.

List of Gauge Manifolds

1- Shikha 5 Foot (see image)

2- Fieldpiece SM380V

3- Testo 550’s

4- Lichamp Gauge Set

5- Yellow Jacket 42004

2. Vacuum Pump: A vacuum pump may seem unassuming, but its role is monumental. It evacuates air and moisture from refrigeration systems before the introduction of refrigerant, ensuring that the system operates efficiently without unwanted contaminants.

List of Vacuum Pumps

1- Xtremepower 3 CFM 1/4 HP (see image)

2- VIVOHOME 4 CFM 1/3 HP

3- Fieldpiece 6 CFM 1/2 HP

4 – Robinair 3 CFM 1/4 HP

5- OMT 4.5 CFM 1/3 HP

3. Leak Detection Tools: Finding elusive refrigerant leaks is a challenge without the right tools. Leak detection tools, including electronic detectors and bubble solutions, play a crucial role in environmental protection and system efficiency by pinpointing these leaks.

List of Leak Detectors

1- Elitech ILD-200 Infrared (see image)

2- Aprvtio ALD-200 Halogen

3- Inficon 705-202-G1

4- Fieldpiece DR82

5- Xetron CLD-100

4. Digital Multimeter: An HVACR technician’s electrical diagnostic prowess relies heavily on a digital multimeter. This tool measures voltage, current, and resistance in electrical components, making it indispensable for troubleshooting electrical issues.

List of Digital Multimeters

1- KAIWEETS Digital Multimeter (see image)

2- AstroAI TRMS 6000

3- AstroAI 4000

4- Astro 2000

5- Klein MM325

5. Pipe Cutters and Flaring Tools: Copper pipes are the lifeblood of many refrigeration systems, and pipe cutters and flaring tools ensure these essential components are accurately cut and shaped for the job.

List of Flaring Tools

1- Super Stars 1/4″ to 3/4″

2- Flexzion 3/16″ to 3/4″

3- Libraton 1/4″ to 3/4″

4- Rigid 41162 377 3/16″ to 3/4″

5- HAUTMEC 3/16″ to 3/4″

6. Pipe Benders: The importance of smooth, kink-free bends in copper pipes cannot be overstated. Pipe benders are the secret to achieving these precise bends without compromising the integrity of the pipe.

7. Thermometers and Thermocouples: When it comes to temperature measurement, accuracy is key. Thermometers and thermocouples help technicians monitor temperatures at various points in the system, assisting in both diagnostics and cooling optimization.

8. Tubing Tools: Properly preparing tubing for installation is a fundamental step in any refrigeration project. Tubing tools, such as deburrers and reamers, ensure that tubing is ready for action.

9. Hex Key Set: Hexagonal screws and bolts are commonplace in refrigeration systems. A set of hex keys is a technician’s trusty companion for swiftly disassembling and reassembling components.

10. Oil Pump and Oil Injector: Lubricating oil is the lifeblood of compressors. Oil pumps and injectors ensure that the compressor functions optimally by delivering the right amount of lubrication.

11. Torque Wrench: Precision matters in refrigeration systems. Torque wrenches guarantee that bolts and nuts are tightened to precise specifications, safeguarding components and maintaining proper seals.

12. Digital Scale: In the intricate world of refrigeration, precision is paramount. This is where a digital scale steps in as a silent but indispensable partner for refrigeration mechanics. Why? Because refrigerants, lubricants, and various chemicals must be added to systems with meticulous accuracy.

A digital scale ensures that the right quantities are added, helping maintain the system’s efficiency, performance, and, perhaps most importantly, the environment. It’s not just about getting the job done; it’s about getting it done right, and that’s where the digital scale shines. So, let’s weigh in on the importance of this often-overlooked tool in the refrigeration technician’s toolkit.

List of Digital Scales

1- Eiltech LMC-200A (see image)

2- Xetron High Accuracy

3- Eiltech LMC-300A

4- Yellow Jacket 68862

5- VIVOHOME Precision Electronic

These tools are the cornerstone of any refrigeration technician’s toolkit. Stay tuned as we dive deeper into each of these essential instruments, unveiling the art and science behind their usage, and why they’re indispensable for refrigeration technicians around the globe.

Air Filters vs COVID-19

MEP Academy Instructor

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September 4, 2023

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In this article we’ll answer a question that we get all the time. What filter, if any, can filter out the SARS-CoV-2 virus which leads to COVID-19, the disease? We’ll show you how efficient the different air filters are at filtering out various items for asthma and allergy sufferers, and the virus that leads to COVID-19.

If you prefer to watch the Video of this presentation, then scroll to the bottom or click on the following link. Air Filters vs COVID-19

The ability of an air filter to remove microorganism, dust, pollen, dust mites, mold spores, pet dander, bacteria and viruses is indicated by a numerical value. This number, which is indicated as a MERV rating, states the filter’s efficiency at removing various sizes of these items. We’ll show you which filters, if any, work the best to protect you from these potentially harmful organisms.

MERV Rating

Minimum Efficiency Reporting Values, or MERVs, indicate the filter’s ability to capture larger particles, those 0.3 microns and larger. The higher the numerical rating, the greater the air filter is at removing particles from the air stream. A MERV-13 is better than a MERV-11 filter at removing particles, but how good are they against bacteria and a very small virus that leads to COVID-19.

Virus and Bacteria Removal

According to ASHRAE, research has shown that the particle size of the SARS-CoV-2 virus that leads to COVID-19 is around 0.1 microns. This is much smaller than what may be picked up by these air filters. As this chart shows, the virus lives in the invisible region, while others like dust, cat dander and human hair are visible to the human eye.

Sizes of various items shown in Microns. Invisible items in black area on chart, including the SARS-CoV-2 Virus.

Luckily, the SARS-CoV-2 virus doesn’t travel through the air own its own. It rides on respiratory droplets and droplet nuclei (dried respiratory droplets) that are predominately 1 micron in size and larger. These filters have various efficiencies at capturing the viruses that are in the 1-to-3-micron range according to ASHRAE.

The SARS-CoV-2 virus riding a respiratory droplet in the 1 to 3 micron range

ASHRAE

As the chart shows, ASHRAE recommends using a minimum of a MERV 13 filter, which is at least 85% efficient at capturing particles in the 1 to 3-micron size range. A MERV 14 filter is at least 90% efficient at capturing those same particles. High-efficiency particulate air (HEPA) filters are even more efficient at filtering human-generated infectious aerosols.

MERV Rating and Air Filter Efficiency for Particle sizes 1 to 3 microns in size

By definition, a HEPA air filter must be at least 99.97% efficient at capturing particles 0.3 micron in size. This 0.3-micron particle approximates the most penetrating particle size (MPPS) through the filter. HEPA filters are even more efficient at capturing particles larger AND smaller than the MPPS. Thus, HEPA air filters are more than 99.97% efficient at capturing airborne viral particles associated with SARS-CoV-2 which leads to COVID-19.

Checkout these HEPA Filters for your Home or Office

HEPA filters can capture and trap microorganisms, including viruses and bacteria, helping to reduce the risk of respiratory infections. So, if possible, use the highest MERV rated air filter with your system, or get a portable HEPA air filter for your room or office. HEPA filters are the most efficient at capturing small microorganisms like the SARS-CoV-2 virus.

Where are HEPA Filters used?

HEPA air filters are used in residential, commercial, and industrial facilities. In homes there are portable types that can be moved from room to room, and others that can be installed in a central air conditioning system serving the whole house.

HEPA air filters are also used along with ULPA filters in cleanrooms, labs, and other spaces requiring a very clean environment.

Asthma and Allergy Management

For individuals with asthma, HEPA filters help reduce asthma triggers like airborne irritants and respiratory allergens. According to the Asthma and Allergy Foundation of America (AAFA), nearly 26 million people have asthma in the United States. There are 4.8 million children under the age of 18, and nearly 21 million adults suffering from asthma. On average, 10 people in the unites States die every day from asthma. A total of 3,517 deaths in 2021.

According to the AAFA over 100 million people each year in the United States experience various types of allergies. Allergies are the sixth leading cause of chronic illness in the U.S. HEPA filters are highly effective at removing allergens such as pollen, dust mites, and pet dander, providing relief to allergy sufferers.

Editorial Process:

Some of the links in this article may be affiliate links, which can provide compensation to the MEPAcademy at no cost to you if you decide to purchase. Our reviews and articles are made by an industry professional experienced in the engineering and construction of commercial buildings.

Air Filters vs COVID-19

HVAC Equipment Cost Database

MEP Academy Instructor

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May 10, 2021

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Are you paying too much for your HVAC equipment? How do you know if the quote you received for your equipment is a fair price? Do you have a method of comparing what you have paid for various HVAC equipment with what is being quoted currently?

Keeping track of the cost of HVAC Equipment allows you to quickly provide budgets and check the cost of equipment before you purchase. This database allows you to easily keep track of the most common HVAC equipment.

HVAC Equipment Cost Database

Using an HVAC Equipment cost database will save you a lot of money by avoiding the costly mistake of paying too much for equipment.

Air Conditioners price per ton and price per square feet historical equipment pricing database — Air Conditioners in Historical Pricing HVAC Equipment Database

Get your copy here. HVAC Equipment Cos t Database

The HVAC Equipment Cost database keeps track of all your equipment quotes or purchases for easy reference and parametric checks, such as cost per ton ($/Ton), cost per CFM ($/CFM)

HVAC Piping Unit Pricing

MEP Academy Instructor

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August 31, 2020

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For an HVAC Piping Estimators the need for quick budgets for the installation of piping is best handled with a spreadsheet of different material types and sizes. Having an estimating software program can make this process a lot easier, as the material pricing is always up to date and can be entered into the spreadsheet quickly. You can get a copy of this spreadsheet to help you price piping fast and efficiently.

HVAC PIPING UNIT PRICING

Often the requirements of the RFP or bidding instructions will call for the price per foot to install piping beyond that which is required by the contract drawings. Such pricing maybe used for change-orders. Having these numbers available and updated often also gives you a quick reference for budgeting projects. It’s good to know when doing job site comparisons of different piping options or during discussions with engineering, what the cost is for the various piping sizes and types of materials.

COST PER FOOT

The cost per foot for the installation of piping needs to include fittings and hangers prorated into the value. It’s best to look at a standard length of pipe and then figure that you will have a Tee and 90 degree elbow in that length.

So for example, using twenty feet of copper water pipe with a Tee and 90 degree elbow plus the hangers to build a unit price would represent a field condition of a fitting every ten feet.

For higher density projects like Hospitals you could put more fittings in your unit pricing. Total those cost up and then divide by 20 to derive at a cost per foot for that particular size and material type.

20 feet of pipe + 2 Fittings + 3 Hangers / 20 = Cost per Foot

If the piping is insulated, you can also put the values in for insulation.

The Estimating Wizard provides two spreadsheets for tracking unit pricing, one for HVAC Piping and the other for Plumbing piping. Get a copy and start tracking your cost per foot, or be prepared to give a quick budget based on your knowledge from your spreadsheet of unit prices. Watch the video below to see how quick and easy it is to track the cost per foot for various sizes and material types.

MEP Academy HVAC Piping Unit Pricing Spreadsheet

The MEP Academy provides a spreadsheet that makes calculating unit pricing simple. The spreadsheet is available by following this link, HVAC Piping Unit Pricing Spreadsheet

HVAC Piping Unit Pricing Calculator Example

In the screenshot above there is a place for you to build your hanger requirements (#1), and a place to put your tax rate and hourly labor rate (#2).

For each size of pipe and material type you would insert the unit cost for Material (#3) and Labor (#4).

Under item (#5) you would build your typical run of pipe and enter the quantity of fittings you might expect for the type of building and system. You would add whatever you think will be required for every so many feet of pipe. In the example above we are showing that for every 20 feet of pipe you will have 1 Elbow and 1 Reducing Tee.

Under item (#6) you would add the cost per lineal foot for insulation if required. You could also look at insulation as a separate value and leave the pipe bare.

Line item (#7) is where you indicate the hanger spacing, and for each hanger you defined under item (#1) you will get the quantity as defined by the linear feet in item (#5) divided by your hanger spacing, which will affect your cost.

Line item (#8) is the calculated cost per linear foot of piping for that size and material type of pipe.

Summary Sheet

After you have all your unit pricing information inputted into the spreadsheet, all you have to do to get a budget for installing piping is to enter the quantity of piping (#9) for each size and material type (#10). The system will automatically calculate the cost (#11) to install that run of piping based on your unit pricing data. The total cost will be shown at the top of the spreadsheet (#12).

Piping Unit Pricing Calculator Summary Page

You can get your copy here. HVAC Piping Unit Pricing Spreadsheet

AC Condensate Drain Sizing and Layout

MEP Academy Instructor

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August 17, 2020

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The proper sizing and layout of condensate drain lines is important for the protection of property and for the proper functioning of the air conditioning equipment.

If you prefer to watch our YouTube version of this presentation, scroll to the bottom.

Condensate Drain Pipe Sizing

The size required for the condensate pipe is dictated by the local code. Enclosed you will find the requirements for many local codes, but be sure to check your code for your local requirements. If the outlet size of the equipment’s condensate drain is larger than what’s shown in this chart then your required to use the larger outlet size.

Slope to be at least 1/8” per foot or 1 percent, that is for every 12” horizontally there must be at least an 1/8” drop vertically.

Condensate drain piping to slope a minimum of 1/8" per every 12" horizontal — Condensate drain piping to slope a minimum of 1/8″ per every 12″ horizontal

Attics or Furred Spaces

If the Air Conditioner is suspended above an inaccessible ceiling, such as a gypsum board ceiling or attic space then you will need to provide a means for protecting the building elements from the overflow of the primary drain and for indicating that there is a leak.

Also, drain pans that are poorly drained can cause water to stay in the pan risking the possibility of algae and bacteria growth. Below are some possible solutions, but as always check your local code for the approved method.

Option 1 – Secondary drain pan with drain piping. This would hang below the Air Conditioning unit in case the A/C units primary pan overflowed. Also, there is a requirement to provide secondary drain piping to a point of termination that would provide notification to the occupants that there is a leak, such as terminating above a window or doorway.

Option 1 - Secondary drain pan with piping terminating in observable location — Option 1 – Secondary drain pan with piping terminating in observable location

Option 2 – An additional drain pipe connection that sits above the primary drain connection and whereby the secondary drain piping terminates in a location to alert the occupants of the clogged primary drain.

Option 2 - Secondary drain piping connection to primary drain pan — Option 2 – Secondary drain piping connection to primary drain pan

Option 3 – Leak detection device that automatically shuts down the Air Conditioner if the primary drain becomes clogged.

Option 3 - Primary drain with leak detection device — Option 3 – Primary drain with leak detection device

Option 4 – Secondary drain pan with leak detection, located beneath the coil that shuts down the unit upon a leak.

Option 4 - Secondary drain pan with leak detection — Option 4 – Secondary drain pan with leak detection

The additional drain pan or drain pan connection shall be provided with a drain pipe that will determinate in an observable area, such as in front a window or above a doorway, and be of a size not less than 3/4”. Secondary drain pan shall not be less than 1-1/2” in height and extend 3” wider on each side of the coil or AC unit.

Secondary drain piping terminating above window. Pipe doesn't have to be visible as shown. — Secondary drain piping terminating above window. Pipe doesn’t have to be visible as shown.

Drain Termination

Where can and can’t you terminate the air conditioners condensate drain piping? There are several options where you can terminate the condensate drain line;

Indirect Drain
Condensate Pump to Indirect Drain
Drywell
Leach pits
Landscaped areas that are properly designed to handle the volume of condensate
To Properly designed stormwater treatment systems.

Indirect Drain

Lavatory tailpiece in the same tenant space as the air conditioner
Laundry standpipe
Janitors Sink
Inlet of Bathtub Overflow – Must be accessible
Collect and send to cooling tower (See description below)

Cooling Coil condensate to sink tailpiece.

The connection to a plumbing fixtures tailpiece has to be made within the same tenant space as the air conditioner cooling coil that is generating the condensate.

Drywell

A drywell can be used for the termination of your air conditioners condensate drain. Check your local code for the specifics, but generally it includes some or all of the following depending on whether it’s for residential or a commercial project:

A minimum size hole, such as 2 foot by 2 foot by 3 feet deep, or a round hole such as 12” diameter by 3 feet deep.
A minimum of 6” of soil or concrete shall provide cover above the rocks
Some form of barrier between the soil and the top of the drywell where the rock begins, such as building paper or plastic
Drywell to be filled with gravel or crushed rock, often with a stated minimum size rock such as 1 inch diameter
The termination of the condensate drain pipe shall connect indirectly to the drywell drain pipe.
The drywell drain pipe to be a minimum of 1-1/2” PVC or other approved material.
Drywell to be at least three feet away from the building structure or any footings.

Drywall for Air Conditioner Cooling Coil Condensate

There are various methods of providing drywells depending on the local code. There are prefabricated drywells that can be used and ones that are made by using a large diameter piece of PVC pipe or similar material.

Some codes will require you to collect the condensate from cooling coil drain pans and return it to the cooling tower if the equipment is served by a cooling tower and the total combined capacity of the HVAC cooling coils exceeds a certain amount like 65,000 btu/hr.

This is a water conservation measure, and there are some exceptions to this requirement, such as if the total capacity of the AC Equipment cooling coils are less than 10% of the total capacity of the cooling tower, or if the location of those AC Cooling coils are in a remote location, far from the tower.

Some locations where you can’t terminate condensate;

Public ways
Sidewalks
Driveways
Alleys

No termination of condensate on public area ways

Excluded from Code Requirements

Excluded from these codes are non-condensing type of equipment like radiant cooling panels that are designed to prevent condensate from occurring by keeping the temperature of the chilled water above the dew point temperature/vapor pressure of the surrounding air. These are system designed to operate in sensible cooling only modes.

Piping Material

The material types that can be used for condensate drain piping varies by jurisdiction but the most commonly cited materials are:

Copper
PVC – DWV
CPVC
ABS – DWV
Polyethylene
Galvanized steel
Cast iron.

Also the use of short radius 90-degree elbows are often prohibited. You can normally use standard fittings until you reach a certain size at which point you might be required to use drainage pattern fittings (DWV)

Traps

Traps are to be installed as required per the manufactures recommendation. No traps are required on the secondary drain pan, this is to allow immediate notification that the primary drain has failed.

Cleanouts

Cleanouts are required in case of plugged drain pipes. Provide as required to prevent the need to cut drain pipes for unplugging. Some of the following maybe used for cleanouts if approved by your local code authority;

Plugged tees
Union connections
Short clamped hoses at the unit (see image above)

When you have more than one air conditioning unit condensate tied to a main condensate pipe, then every change of direction shall have some method of cleanout. Check your local code as this maybe a requirement for even a single air conditioners condensate piping.

Condensate Pumps

Condensate pumps can be used to elevate the condensate vertically to a point where it will then discharge into a code approved gravity sloping condensate drain line. The condensate pump should be interlocked with the Air Conditioning Unit to prevent its operations if the condensate pump is inoperable.

Checkout these Condensate Pumps

Please remember that code requirements are always changing, so check for the most current code in your area at the time of design and installation. Or ask an inspector for the current installation practice.

Refrigerant Line Sets

Video of this Article

MEP Academy Estimating Spreadsheet

MEP Academy Instructor

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July 14, 2020

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Having an MEP Academy Estimating Spreadsheet that automates portions of your estimates, will save you valuable time that could be used to make more sales. All aspects of the cost of furnishing and installing an HVAC and/or a Plumbing system is contained in one spreadsheet made specifically for the MEP industry. For plumbing only see below.

For a Plumbing only Spreadsheet, use this Commercial & Residential Version. Plumbing Only. For a simple Residential HVAC & Plumbing Spreadsheet. Residential version.

Dashboard

The Main Dashboard provides you with all the information you need to make a quick decision on whether to make further adjustments, or if one of the metrics looks out of place based on historical data. The Dashboard gives you a quick overview of all that is going on within the Estimating Spreadsheet.

Estimating Dashboard within the MEP Academy Estimating Spreadsheet

Your MEP Academy Estimating Spreadsheet needs to be able to handle rental equipment, general conditions, subcontractors, piping and plumbing takeoffs, sheet metal, labor rate tables with crew mix capabilities, , and a bid summary. Each sheet in the estimating spreadsheet automatically calculates the values you enter, showing you a new total bid amount.

Will cover portions of the MEP Academy Estimating Spreadsheet starting at the back of the Excel spreadsheet and working our way toward the front summary page last.

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Labor Rate & Crew Mix Table

Choose your crew mix based on the level of experience and the different pay scales based on each project. Pick any combination and quantity of tradesman based on the requirements of the project.

Labor Rates and Crew Size within the MEP Academy Estimating Spreadsheet

There is a separate crew labor rate for HVAC Piping Shop & Field, Sheet Metal Shop & Field, and Plumbing.

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HVAC & Plumbing Equipment

Enter the project equipment price and labor to rig the HVAC and Plumbing equipment into place. Compare supplier pricing easily side by side. The MEP Academy Estimating Spreadsheet automatically selects the lowest bidder but lets you override that decision.

HVAC Equipment page within the Estimating Spreadsheet

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General Conditions

Do you need a jobsite trailer or onsite management? Enter the quantity and level of the staff required to run the project, whether one person or dozens. Set the quantity and duration of each general condition, along with the rate. General Conditions is broken down into three sections as follows: #1 – Management, #2 – Construction Office (Non-Reoccurring Expenses), and #3 – Construction Office (Reoccurring Expenses).

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HVAC & Plumbing Subcontractors

HVAC & Plumbing contractors often subcontract out for Air & Water Balance, Sheet Metal & Piping Insulation, Water Treatment, Building Automation, Excavation and other specialty trades that they don’t self-perform. This spreadsheet was made especially for the HVAC & Plumbing contractor and their most often used subcontractors.

Subcontractors – Rentals – GC’s – Engineering Pages

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Plumbing Fixtures

For those contractors that do plumbing the following Plumbing Fixture sheet will give you a place to record your vendors quotes and the labor it takes to install each type of fixture. What is also revealed is the overall cost per fixture.

Plumbing Fixtures page within the Estimating Spreadsheet

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MEP Specialty Sheets

Each trade has a specialty sheet for those items that aren’t considered equipment or a fixture, but for which there is a cost impact. The MEP Academy Estimating Spreadsheet includes Sheet Metal, HVAC Piping & Plumbing Specialty sheets.

HVAC and Plumbing Specialty Pages within the Estimating Spreadsheet

Specialty Sheet In Estimating Spreadsheet — Specialty Sheets in Estimate Spreadsheet

Material & Labor Summary Sheets

You will find a Sheet Metal, HVAC Piping & Plumbing material & labor summary sheets where all of the other specialty sheets are summarized for your review and last minute edits. Each sheet will be divided between field & shop fabrication work. The first section covers the field installation items.

Sheet Metal Material and Labor Summary – Estimating Spreadsheet

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Field Summary Section

This is where you will put your material takeoff information for the following:

Rectangular & Round Ductwork
HVAC Piping
Plumbing Piping

This is also where the other sheets that you filled out will be summarized, such as the following;

HVAC & Plumbing Specialties
HVAC & Plumbing Equipment Labor
Plumbing Fixtures

Material & Labor Summary Sheet in Estimating Spreadsheet — Material and Labor Summaries

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Each of the field labor summary sheets contain a row to add for the following

Material Handling
Consumables
Punch List
Cleanup
Detailing
Supervision

Shop Fabrication Summary Section

For those of you that have a fabrication shop, there is a section to add material and labor.

Rentals

For those HVAC air conditioning and Plumbing projects that require a crane, fork lift, scissor lift or any other equipment that you don’t own but will be required on the project. Having a spreadsheet that maintains a list of the most common equipment you normally rent along with their rental rate will save you time and money while avoiding having to call for pricing on every job.

Engineering

If you do your own design then you should have a sheet of each of the personnel responsible for spending time on the engineering task. If you’re doing design/build work, but don’t do the engineering yourself, but hire a third party, then you should add some engineering review time. It’s your responsibility to manage your third-party engineer to make sure they design within your cost parameters.

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Estimate Summary

All of your estimates are summarized on the last tab of the MEP Academy Estimating Spreadsheet for easy review. You can quickly scan each of the categories to see where all the project cost has shown up. There is the labor and material summary for HVAC Sheet Metal, HVAC Piping, and Plumbing and another section for Subcontractors, General Conditions, Rentals, etc.

Estimating Spreadsheet Summary Page

Estimating Summary — MEP Academy Estimating Spreadsheet Summary

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Bid Risk Assessment Form

The MEP Academy Estimating Spreadsheet contains a bid risk assessment form that rates the success of winning any particular project that you are contemplating pursuing. The risk assessment form will help you determine if the project is worth bidding based on a set of questions that rate your answers.

The answers to these questions will give you a score from which you can use to see how the project rates on a scale of risk and reward. The total risk assessment score will also inform you which level of approval is required within your company depending on how you rate your risk values as the example shown below. The total score is 25, which according to this contractor would require the Vice President to sign-off on the project or approve the decision to pursue bidding on the project.

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MEP Academy Estimating Spreadsheet Summary

The MEP Academy Estimating Spreadsheet is used to gather all the information for estimating a project, putting it into a format where you can make quick adjustments and decisions while the spreadsheet gives you an immediate update on the price.

Purchase this spreadsheet at its currently reduced price of ONLY $245.00, which usually sells for ~~$599.00~~

Watch the YouTube video below to see the MEP Academy Estimating Spreadsheet in action.

Flow Meters

HVAC Engineering

MEP Academy Instructor

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October 6, 2024

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In this article, we’ll look at flow meters, exploring the different types used to measure liquids, gases, and steam. Whether you’re working with water, steam, or natural gas, understanding the right flow meter for your application is critical for accuracy and efficiency. We’ll show you how to calculate the flow based on the measured data.

If you prefer to watch the video of this article, then scroll to the bottom.

Inline Magnetic Flow Meter

Magnetic flow meters measure flow based on Faraday’s law of electromagnetic induction. Two opposing magnets create a magnetic field that the fluid passes through. As the fluid passes through the magnetic field, the electrodes detect the voltage, which is proportional to the fluid flow.

This flow meter will require electrical power or an onboard battery. The information gathered from the meter can be sent to a building automation system for various sequence of operation control strategies.

There are no moving parts or obstructions in the flow path. This provides a very low to no pressure drop. This makes them a low maintenance meter while also being easy to calibrate. You will need at least 3 or more diameters of upstream straight pipe and two diameters for downstream. This is to ensure accurate readings. Check the manufacturers literature as they can vary.

Because these are inline meters and have accuracies ranging from ±0.2% to ±1% of the flow rate they are more expensive than other types especially as the pipe sizes become larger. For these reasons an inline magnetic flow meter would not be the best choice for HVAC applications unless high accuracy is required.

Insertion Turbine Flow Meter

Uses one or more turbine wheels that spin as fluid flows through the system. The rotational speed of the turbine is proportional to the flow velocity. As the turbine spins the meter keeps track of the number of complete revolutions the wheels make. The revolutions per minute is then easily converted to velocity and with a known pipe size a flow rate in GPM or liters per second can be determined.

These meters are inserted into the flow path rather than being inline, minimizing disruption to the system, while making them more affordable. These meters are more commonly specified for HVAC projects for there ease of installation and their lower price. With the use of a hot tap some of these flow meters can be installed into a pressurized and actively flowing pipe. The insertion turbine meter will require additional upstream and downstream straight pipe lengths than that required for the inline magnetic flow meter.

There will be a low pressure drop caused by the turbine wheel, and since they have moving parts, the maintenance will be greater in addition to the time between recalibrations.

Inline Vortex Flow Meter

By placing an object in the flow path that creates vortices that can be measured by the meter a frequency is created that is proportional to the flow rate. There are sensors located along the shredded vortex that measures the pressure changes. The frequency at which each vortex is shed is directly proportional to the velocity of the flowing liquid.

There is also the option to provide insertion type vortex flow meters.

The flow meter has a moderate pressure drop due to the bluff body obstructing the flow, but usually acceptable in most applications.

Clamp-on Ultrasonic Flow Meter

Ultrasonic sound waves are used to measure flow. Transducers are clamped onto the exterior of the pipe, and sound waves are sent through the pipe wall and fluid in both directions. The difference in sound wave transit time is proportional to the flow rate. The transducers act both as a transmitter and a receiver, alternating between sending and receiving sound waves.

There is no pressure drop, as there is no direct contact with the flow or intrusion into the pipe.

The flow meter is ideal for non-invasive measurement of flow in water, natural gas, and liquid applications. Common in applications where retrofitting is required, such as existing pipelines, or where contamination must be avoided.

There is a small handheld meter that can be used for smaller pipes.

Calculating Flow

To determine how much water is flowing through the system a calculation is done to derive at gallons per minute or liters per second. The flow meters determine the velocity which needs to be converted to flow based on the pipe size.

ASHRAE provides recommended velocities for various pipe sizes and whether the system is constant or variable flow. Chapter 22 of ASHRAE’s fundamentals handbook recommends that for an 8-inch pipe in a variable flow system with greater than 2,000 operating hours a velocity of 8.98 feet per second or 2.74 meters per second be used. We’ll use 9 feet per second.

To calculate flow, we’ll need to know the area of the pipe because flow requires us to know velocity and area. For an 8 inch or 200-millimeter pipe we need to determine the area. For an 8-inch pipe the area equals 0.349 ft2. The GPM equals velocity times the area times the conversion factor. The conversion factor equals 448.8312 which converts cubic feet per second to gallons per minute as follows. 1 cubic foot of water equals 7.48052 gallons.

GPM equals feet per second (Velocity) times square feet (Area) times 448.8312 which is the conversion factor.

GPM equals 9 feet per second times 0.349 square feet times 448.8312 equals 1,410 GPM

Each of these flow meters has specific strengths and limitations, so the best choice depends on factors like the fluid being measured, temperature requirements, and system pressure drop constraints.

Flow Meters Explained – Magnetic Inline, Insertion Turbine, Vortex Inline and Clamp-on Ultrasonic

Understanding Dry Bulb, Wet Bulb, and Wet Bulb Depression

HVAC Engineering

MEP Academy Instructor

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September 25, 2024

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Understanding Dry Bulb, Wet Bulb, and Wet Bulb Depression

Dry Bulb Temperature and Wet Bulb Temperature are both essential in understanding air properties, especially in HVAC applications. We’ll explain these two temperatures and how they relate to evaporative cooling and relative humidity using a psychrometric chart.

If you prefer to watch the Video of this presentation, then scroll to the bottom of this page.

Dry Bulb Temperature

Dry Bulb is the temperature of the air measured by a regular thermometer, without considering moisture. It’s measured using a standard thermometer exposed to the air but shielded from direct solar radiation. Dry bulb temperature is what people commonly refer to as “air temperature.” It indicates the heat level of the air and is crucial for thermal comfort and HVAC system design.

When trying to understand the current air conditions, one must also look at the wet bulb temperature, not just the dry bulb temperature, as it accounts for humidity and provides a more complete picture of heat stress and cooling potential.

Wet Bulb Temperature

Wet Bulb is the temperature a parcel of air would have if cooled to saturation (100% relative humidity) by evaporation. The wet bulb temperature will always be lower than or equal to the dry bulb temperature because evaporation absorbs heat. It’s measured by wrapping a wet wick around a thermometer bulb and allowing evaporation to cool the bulb, with the resulting temperature reflecting the cooling effect of moisture in the air.

As water evaporates, the temperature drops, and this lower reading is the wet bulb temperature. Wet bulb temperature helps assess the amount of moisture in the air. It is used in processes like evaporative cooling and determines the cooling efficiency in such systems.

Wet Bulb Depression

The Wet Bulb Depression is an indicator of how much the air can cool down through the process of evaporation. The larger the temperature depression, the drier the air, which means it has more capacity to absorb moisture.

We can see on this psychrometric chart that a dry bulb temperature of 85 Fahrenheit minus the wet bulb temperature of 55 Fahrenheit equals a wet bulb depression of 30 Fahrenheit or 16 Celsius

Wet Bulb Depression = Dry Bulb Temperature – Wet Bulb Temperature

A high Wet Bulb depression means that there is significant potential for evaporative cooling. For example, in hot, dry environments, where the Dry Bulb Temperature is much higher than the Wet Bulb Temperature, evaporative cooling (like using a swamp cooler) is very effective.

A low Wet Bulb depression (where Dry Bulb Temperature is close to Wet Bulb Temperature) indicates the air is near saturation with moisture, so there is less cooling potential through evaporation.

Relative Humidity (RH)

Relative Humidity is the percentage of moisture the air holds compared to the maximum it can hold at that temperature. When the Dry Bulb Temperature and Wet bulb temperature are close together, the relative humidity is high because less evaporation is occurring. When Dry Bulb and Wet bulb temperatures are far apart, the air is dry, and relative humidity is low, as there is more capacity for moisture to evaporate into the air.

We can see that the relative humidity is at 10%.

If the wet bulb temperature increased to 60 F or 15 C, then the wet bulb depression decreases to 25For 14C. We can see that the relative humidity has increased to 20%.

If the wet bulb keeps climbing and the dry bulb stays the same, the wet bulb depression keeps shrinking, while the relative humidity increases. This informs us that as the wet bulb gets closer to the dry Bulb Temperature the relative humidity increases. For efficient use of a swamp cooler or evaporative cooler, a wet bulb depression of at least 15°F to 20°F (8°C to11°C) or more is generally required. This means the difference between the dry bulb temperature (ambient air temperature) and the wet bulb temperature should be at least 15°F (8°C), indicating low enough humidity for effective evaporation and cooling. Evaporative cooling is best suited for hot, dry climates with low humidity.

Dry Bulb, Wet Bulb and Wet Bulb Depression

Here the dry bulb and wet bulb temperatures are the same at which point we have 100% relative humidity, and we have also reached the dew point line where condensate occurs. The wet bulb depression is zero because the dry bulb and wet bulb temperatures are the same.

100% Relative Humidity equals a Zero Wet Bulb Depression

Dew Point Temperature

Dew point is the temperature at which air becomes fully saturated (100% Relative Humidity) and moisture condenses into liquid (dew). If Dry Bulb Temperature falls to the dew point temperature, condensation occurs, leading to dew or fog. When the Wet bulb temperature is close to the DBT, the air is near saturation, and the dew point is close to the current temperature, meaning high humidity levels.

Understanding Dry Bulb, Wet Bulb and Wet Bulb Depression

A Guide to Refrigerant R454B and R32

MEP Academy Instructor

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September 10, 2024

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Why are we changing refrigerants again? As the battle against high Global Warming Potential refrigerants rages on, air conditioning manufacturers are left feeling like they’re in a never-ending game of limbo—constantly asking, how low can you go with each new refrigerant mandate. Refrigerant R454B and R32 are becoming the new darlings of the industry for smaller commercial and residential systems.

If you prefer to watch the video of this presentation, then scroll to the bottom.

R454B has a lower Global Warming Potential than R410A. R410A is being phased out like R11, R12 and R22 were. R454B has a Global Warming Potential of 466, while R410A has a value of 2,088, which is above the new threshold of 700. The higher the value the worst the refrigerant is for the environment. R32 comes in at 675, just under the mandate.

The questions we’ll answer are, how much does R32 and R454B cost compared to other refrigerants? Will I need new tools and equipment to work with R32 and R454B? Can I use R32 or R454B as a drop-in replacement for an existing R410A, or R22 system?

Effects of Global Warming Potential on Refrigerant Cost

The cost per pound of refrigerant is influenced by its Global Warming Potential (GWP) and whether it is being phased out or has restricted production:

Refrigerants with higher GWP values are more environmentally damaging and are increasingly subject to regulatory restrictions. As regulations tighten, such as those under the Kigali Amendment to the Montreal Protocol, the demand for low-GWP refrigerants rises. This demand shift can lead to a decrease in the availability of high-GWP refrigerants, driving up their cost.

The effects of GWP on Refrigerant Cost per Pound

When a refrigerant is phased out or its production is restricted, as seen with R11, R12 and R22, the supply diminishes while existing systems still require the refrigerant for maintenance. This limited supply, combined with ongoing demand, results in a significant increase in cost per pound. R410A is currently available at a reasonable cost per pound but that will start to change as production decreases and other refrigerants with lower global warming potential values are produced and installed.

Refrigerants with high GWP values and those subject to phaseouts typically become more expensive over time due to increased regulatory pressure and reduced availability.

Daikin is currently a manufacturer of R32 and residential units that use R32. New R454B AC systems will become more available in 2025. The manufacturing or importing of R-410A residential and light commercial air conditioning products is prohibited starting January 1, 2025.

Your price per pound will vary based on how much refrigerant you buy from your supplier.

Can I convert an R410A System to Refrigerant R454B

R410A systems are not compatible with R454B due to differences in refrigerant characteristics, including pressure, temperature glide, and flammability. R410A is a class A1 refrigerant, while R454B is a class A2L refrigerant which is slightly more flammable. As a result, retrofitting R410A systems to use R454B is not advisable. New systems specifically designed for R454B will be required.

R410A operates at higher pressures than R454B, making the compressor and condenser less compatible with a lower pressure refrigerant. Additionally, the components in systems designed for R410A are not suitable for use with lower flammability AL2 refrigerants like R454B. Before charging the system with R454B, you must replace these components with ones that are designed to safely handle a slightly more flammable refrigerant.

Refrigerant Comparison Chart. Can you drop-In R454B or R32 into and Existing R410A or R22 system

R-454B is not a drop-in replacement for R-410A or R22. While R-454B shares many characteristics with R-410A, its use is restricted by codes and regulations to systems specifically designed for it.

The same is true for R32. R32 is not a drop-in replacement for R410A or R22.

Can I use my existing tools and equipment on a R32 or R454B system?

A refrigeration technician might be able to use their existing R410A or R22 manifold gauges, leak detectors, vacuum pumps, refrigerant recovery machines, and other tools directly with the new R32 or R454B refrigerant systems. You will need to confirm with the manufacturer to see if it’s approved for multiple refrigerants. This is because R32 and R454B are classified as an A2L refrigerant. These refrigerants are mildly flammable, and may require tools that are specifically rated for use with A2L refrigerants.

We have found new gauge manifolds that are rated for all four refrigerants discussed here. It’s just a matter of buying the right equipment and tools. Never use a tool or piece of equipment that is not specifically approved for the refrigerant in question. You may have older tools that weren’t built to handle the new refrigerants, in which case you’ll need to buy new ones.

To work with R32 and R454B, technicians will need to use tools and equipment that are compatible with A2L refrigerants. This includes gauge manifolds, recovery machines, and vacuum pumps that are designed to safely handle the flammability of refrigerants that are classified as A2L refrigerants. Using the correct equipment is crucial to ensure safety and compliance with regulations when working with R32 or R454B systems.

Can I use the existing Refrigerant Piping

When changing from an R22 or R410A system to an R32 or R454B system, the refrigerant piping generally does not need to be replaced. This is provided that the existing piping is in good condition and appropriately sized for the new refrigerant. R32 often requires smaller pipes than R22.

However, it’s crucial to ensure that the existing piping is thoroughly cleaned and free of any residual oil or contaminants from the previous refrigerant. R454B, like other A2L refrigerants, requires the use of specific lubricants (such as POE oil) that are compatible with the new refrigerant. The system may need to be flushed to remove any incompatible oil or residue before charging with R454B.

Additionally, the piping should be carefully inspected for leaks and pressure-tested to ensure it can handle the operating conditions of the new refrigerant. If the existing piping is in poor condition or not properly sized, replacement may be necessary.

See how the latest Refrigerants compare to the older R410A, R22, R12 and R11

VAV Laboratory Fume Hood Control

MEP Academy Instructor

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September 2, 2024

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In this article, we’ll explore one effective method for managing VAV systems in laboratory settings, focusing on the sequence of operations that ensures a safe and energy-efficient environment.

If you prefer to watch the video of this presentation, then scroll to the bottom.

A common strategy for addressing exhaust and supply requirements while minimizing energy consumption is to implement a variable air volume (VAV) lab control system. This system can be as straightforward as a single exhaust fan connected to two variable-volume fume hoods, or it can scale up to include multiple fans that activate based on laboratory demand.

No matter the size of the lab, each VAV fume hood is equipped with an exhaust airflow control valve to regulate airflow through the hood. Typically, hoods used for standard research are connected to a manifolded exhaust duct that leads to roof-mounted fans. Additionally, the laboratory space is supplied with fresh air through a duct with a modulating damper to control the air’s volumetric flow.

A VAV lab system is managed to maintain a safe environment by use of the following.

Space Pressurization

Laboratories typically operate under negative pressure to contain fumes and odors. To achieve this, the control system is configured to exhaust more air than is supplied. The amount of exhaust air required is directly related to the Air Changes required, Fume Hood airflow capacity, and or the amount of conditioned supply air needed based on heat gain driven labs.

Chemical Fume Hood Flow

The VAV fume hood is equipped with a fume hood monitor, sash position indicator, controller and an airflow control valve that adjusts the airflow based on the position of the sash. While exhaust velocities vary by application, the use of 100 feet per minute is often used. If you have a 6-foot fume hood with an open sash height of 24 inches, then the volume of air would be 6-feet times 2-feet equals 12 square feet times 100 feet per minute, equals 1,200 CFM. An 18-inch open sash would equal 900 CFM. In a lab that measures 64 feet in length by 32 feet wide with a 10-foot ceiling at least 2,048 CFM would be required to achieve the 6 air changes required for this lab. If you want to learn more on how to calculate air changes per hour see our other video.

Laboratory Fume hoods with Venturi type airflow Valves

Lab Airflow Valves

A VAV laboratory controller maintains negative pressure by dynamically adjusting the fume hood exhaust valves, general airflow exhaust valves, and supply airflow valves in response to real-time conditions.

Fume Hood Exhaust Valves

The controller modulates the fume hood exhaust valves based on the sash position. When a sash is opened, the valve opens further to increase the exhaust airflow, ensuring that fumes are effectively captured and removed.

Laboratory Airflow Valve - Phoenix Style Lab Airflow Valve — Laboratory Airflow Valve

General Airflow Exhaust Valves

These valves control the overall exhaust from the lab space, beyond just the fume hoods. The controller adjusts these valves to maintain the desired negative pressure in the lab, ensuring that air flows from adjacent areas into the lab, preventing contaminants from escaping. If the fume hoods are not being used, then the General Exhaust valve will increase its airflow to maintain a negative pressure based on the position of the supply valve.

Supply Airflow Valves

To maintain balance, the controller also modulates the supply airflow valves. As exhaust airflow increases or decreases, the supply airflow is adjusted to ensure that the lab remains at a slightly negative pressure. This ensures that the lab draws in clean air from adjacent spaces, rather than allowing potentially contaminated air to escape the lab.

By coordinating the adjustments of these three types of valves, the VAV laboratory controller effectively maintains a consistent negative pressure, ensuring a safe and controlled lab environment.

Sash Position

As the sash opens, the sash sensor detects the change and signal the fume hood controller to adjust the exhaust airflow control valve to open, ensuring the desired airflow and maintaining a safe hood velocity. When the sash closes, the valve adjusts to a specific level to sustain the required face velocity. As the sash is moved to a new position the controls will respond within seconds to reposition the exhaust airflow control valve to maintain the required face velocity. This requires that the exhaust airflow control valve be able to adjust flow (CFM) from full load to the minimum required. The valves are pressure independent and will maintain the required flow when the overall system pressure fluctuates.

Fume Hood Monitor

The fume hood monitor will indicate the current velocity. There may. be a green light indicating normal operation, and a yellow light when the velocity drops below normal. Once the velocity drops too low or there is a system failure the fume hood monitor will show a red light and produce an audible alarm to alert the room occupants of a potential unsafe condition and to close the sash.

If the user spills a toxic or hazardous substances within the hood, the user can push the purge button on the hood monitor. This will close the sash to contain the contaminants.

Duct Pressure and Bypass Air

Monitoring duct pressure between chemical fume hoods or other exhaust points ensures the system maintains the appropriate negative pressure. This is to keep the lab space negative, even when VAV hood sashes open suddenly. This pressure monitoring also prevents excessive negative pressure, which could damage the exhaust valves or ductwork.

A crucial aspect of controlling duct pressure is adjusting the capacity of the exhaust fan(s) that draw air from the system. While there are various methods to regulate fan capacity, including variable frequency drives. The most common approach is to use a bypass air plenum with a modulating damper.

The bypass air plenum is located either beneath an inline fan or next to a scroll-style centrifugal fume exhaust fan. It includes a modulating isolation damper that disconnects the fan from the duct system when not in use. When sashes are closed and duct negative pressure increases, the bypass damper allows outside air to flow into the fan. This reduces the amount of air pulled from the exhaust system when hood demand is low. The benefits of this setup include:

Laboratory Exhaust Fan with Bypass Damper control

Lab Exhaust Fan

Stable operation of the exhaust fan, ensuring consistent nozzle velocity and plume rise. Exhaust fan stack velocity is crucial in laboratory fume hood exhaust systems because it ensures that hazardous fumes and contaminants are effectively dispersed into the atmosphere, away from building occupants and nearby areas. A sufficient stack velocity creates a high-velocity plume that carries pollutants to a safe height.This minimizes the risk of re-entrainment into the building’s air supply and reducing the exposure of nearby personnel to harmful chemicals. This helps maintain a safe and compliant laboratory environment.

Quick response to changes in duct pressure.

Energy savings, as reduced exhaust from the lab lowers the demand for tempered supply air

The opposite occurs when the sashes begin to open. As the VAV hood valve opens, the duct pressure becomes less negative, and the bypass dampers begin to close. This adjustment draws more air from the lab exhaust system, while the make-up air increases to maintain proper system pressure.

Summary

Lab exhaust systems are essential for ensuring a safe environment in and around laboratory facilities. However, managing chemical fume exhaust, creating high-velocity plumes, and handling 100% outside air can result in significant energy consumption. By implementing a VAV lab system and providing proper training for lab users to close their sashes when not in use, it is possible to maintain a safe environment while also reducing overall energy usage.

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