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Clean Air Buildings Database

Website CAB
Website ACH
Smartphone FVR

The CAB is a public database that contains information on the ventilation performance of actual facilities. It is closely integrated with the ACH Calculations Tool (ACT) which allows users to quickly enter data to calculate the ventilation performance levels in the rooms in a facility and save it in the public Air Changes Per Hour (ACH) database. So there are 2 databases, the CAB which sumarizes the ventilation of a building and the ACH which has all the room details. The intent of this database is to build awareness on the importance of Clean Air in all our facilities and realize that ventilation is about ACH levels and that the ACH levels in all our buildings must be disclosed.

Everyone is encouraged to add facilities into the CAB and ACH databases especially the general public. If you add your facility, you can print and post the Clear Air Building Certificate showing your occupants that you care about the ventilation in your facility. Anyone can add a facility. Just make sure you have reasonable data before you print and post the certificate.

These are ventilation education links:

This is the ACH database link: ACH Calculations Tool

The Facility Ventilation Reporting service allows users to fully navigate through the entire CAB and ACH databases. Visiting a facility, check out the ventilation. If there is no data, enter it using this service. There is also a Smartphone FVR version.

Website Facility Ventilation Reporting



Casual Visitors

 & New Users

Visiting a facility, view status panels

Quick Visitor Onservations


Site Surveyors

 & Experienced Users

Search or Enter CAB Data

Search or Enter ACH Data

Enter CAB data

Check or Add a building, airplane, train, or bus.

A building ventilation system is a life support system.

If the ventilation is not working properly people will be infected by airborne contagions.

Ventilation performance is key to ensure that the risk of infection is minimized or eliminated in a room.

Ventilation is measured in terms of Air Changes per Hour or ACH.

If the ACH is zero people will be infected by an airborne contagion.

As the ACH level increases the risk of infection drops.

For hospital rooms with airborne contagions the CDC recommends a minimum of 12 ACH.

The Heating Ventilation and Cooling (HVAC) systems and UV systems are the primary approaches used to ventilate buildings.

Many  buildings have poor maintenance with closed off vents, failed fans, or poor operations where the system is turned off when people are present.

Many  buildings have systems that are too small.

The Facility Ventilation Reporting APP allows people to take control of their environments and examine the ventilation rates of the buildings that they visit.

Anyone can add buildings to the database if there is no data.

The CAB data is a summary of a facility.

The ACH data has multiple rooms found in a facility.

When there is real time data available from the building, it is reported and available from the FVR APP.

Learn More: Building Ventilation

How can I do this: Ventilation Site Survey

Where to find data: Finding Facility Data

Example Reports: LAX Los Angeles International Airport . Hawaiian Airlines . Airplane 767-300 . Philadelphia Restaurant Program

Example Certificate

The COVID-19 disaster has exposed the importance of clean air within buildings. The guidance throughout the disaster has been for building owner operators to check their ventilation systems and if needed perform reasonable improvements. Many building owners and operators have been proactive and they have taken the guidance seriously and improved their ventilation systems.

Ventilation Education Information

From Time Magazine: If We're Going to Live With COVID-19, It's Time to Clean Our Indoor Air Properly, Edward A. Nardell is Professor of Global Health and Social Medicine, Harvard Medical School.

COVID-variants may be with us for years to come, and this will certainly not be the last respiratory virus pandemic. We have long suffered from annual contagious respiratory infections, but exceptionally low rates of influenza and common colds during COVID-precautions have demonstrated that not all of this suffering need happen. So, we need to think clearly and scientifically about how better we can reduce the spread of viruses indoors especially when and where masks will no longer be in common use.

Are there effective engineering controls that can help make indoor environments truly safer?

Yes, the purpose of this piece is to emphasize the importance of focusing on air disinfection in the rooms where person to person aerosol transmission is occurring.

Link to the full article.

Buildings must comply with local building codes and many assume that establishes the ventilation performance requirements that must be met. However, that is an incorrect assumption. The building codes only establish the minimum ventilation requirements that must be met and buildings can exceed those minimum ventilation performance requirements. The other issue is the building codes do not represent what is needed for airborne contagions except for hospitals. So elite buildings will have great ventilation equal to or exceeding hospital ventilation performance levels.

Some buildings exceed the minimum ventilation performance requirements and they are buildings that were built in the 1920's, 30's, 40', 50's and 60's that were retrofitted with HVAC systems. Their performance levels are high and they exceed local building codes. There are also newer buildings that exceed local building codes with very high levels of ventilation performance requirements and they are elite buildings.

When the energy crisis happened in the last century, there was a massive push to reduce energy consumption and this resulted in significantly reduced ventilation levels. With the rise of sustainability in this century there is an additional push to reduce energy consumption and this is resulting in a further push to reduce ventilation in buildings. Many are now advocating that a building ventilation system just provide enough ventilation to prevent CO2 poisoning. It is known that just maintaining the CO2 levels is an extremely low level of ventilation where airborne contagions will make people sick.

Currently there is a battle behind the scenes between engineers and scientists that want proper ventilation performance requirements placed into all building codes and those that are fighting this effort. Those that are fighting this effort are: (1) the building owners that quickly realized during the energy crisis in the last century that they could save significant amounts of money and (2) those pushing for reduced energy consumption to reduce the effects of global warming. Those pushing for reduced energy consumption have impacted local building codes and now older buildings with high ventilation performance levels are being forced to lower their ventilation system performance levels. This is a serious battle and it is a challenge for this generation in this century.

A building ventilation system is a life support system and if it does not work properly people will be harmed.

It is clear that COVID-19 is spread by inhaled aerosols. Outdoors, dilution of aerosols are infinite although the time it takes to dilute clouds of aerosol depends on air movement. Imagine how a cloud of cigarette smoke lingers or dissipates depending on whether there is a breeze. Indoors, aerosols linger much longer than outdoors, often long enough to be inhaled by someone sharing the same space. If you breath in an indoor setting where other people are also breathing, if the ventilation is poor, you will breath in some of the air that someone else exhaled.

Ventilation is the way that the risk of indoor airborne infection is reduced.

One ACH (air change per hour) happens when a volume of air equal to that of the room enters and leaves over a period of one hour. For hospital procedure rooms, the CDC recommends 6 to 15 ACH with infection free outdoor air, or air that has been filtered or decontaminated. For rooms with airborne contagions the CDC recommendation is 12 ACH. We know that people will be infected in rooms where the ventilation is 0 or 1 ACH. We also know most existing ventilation systems are on demand systems, which means there is no ventilation (0 ACH) until the system turns on to either cool or heat a room. Most systems have a fan mode but no one is turning on the fan mode on these systems. We also know that most systems are sized to be 4 ACH which is a marginal ventilation performance level.

The CAB is a result of research on COVID-19 from a systems perspective that began in March 2020. The findings are summarized as follows:

There is more information at the following links:

.

Finding Facility Data

If you are a facility owner or operator, ask your HVAC company to provide you with the data. If you plan to visit a facility, you can use the Internet to try and find the ventilation data for the facility you plan to visit. If you are already in a facility, you can do a rough assessment and gather data using observations. It is amazing how accurate this broad assessment of a facility without tools can be and it is a very reasonable source of data. Keep in mind that when the term facility is used this includes airplanes, trains, and busses.

There are 2 types of ventilation: Natural Ventilation and Mechanical Ventilation. Natural ventilation could be augmented with mechanical ventilation. For example in a resort setting a restaurant may have massive natural ventilation and it may be augmented with a mechanical HVAC system to add cooling or heat as needed for comfort.

Natural Ventilation

Natural ventilation is accomplished with open windows and doors. The following are some guidelines to estimate the ACH for natural ventilation. The following ACH estimates come from the WHO in a document on natural ventilation; Estimated air changes per hour and ventilation rate for a 7 m X 6 m X 3 m ward.

Openings

ACH

Ventilation rate
(l/s)

Open window (100%) + open door

37

1300

Open window (50%) + open door

28

975

Open window (100%) + closed door

4.2

150

The natural ventilation also can be estimated by treating the open area to the outside as a vent and estimating the Feet Per Minute of air movement through the opening. That estimate can be accomplished using the methods for mechanical systems described further in this procedure. These estimates can easily approach 60 ACH when large entry ways are left open to allow for massive natural ventilation.

Outside ventilation is a form of massive natural ventilation and ACH estimates can range from 60 to 120+ ACH depending on the wind speed. A wind speed of 1 mile per hour will move 5,280 Feet Per Hour of air past a person. This is 5,000+ ACH assuming a person is breathing within a 1 cubic foot space around the head. Even if they are in the direct trajectory path of an infected person, it is unlikely that the infected air will have sufficient concentration to cause any issues unless they are directly talking at the person with no ability to dilute and disrupt the infection cloud. Crowds are a scenario where this infection route may surface. Court yards will have blocked airflow but unless their is a roof like structure, it is very unlikely that low ACH levels will surface.

Based on the above discussion the following ACH levels can be applied to the following Natural Ventilation scenarios.

Natural Ventilation Scenario

ACH
min

ACH
max

Comments
Open Windows

4.2

4.2

WHO Natural Ventilation for Infection Control in Health-Care Settings
Open Windows and Doors

28

37

WHO Natural Ventilation for Infection Control in Health-Care Settings
Open Entry

37

60

Observations 4 X 8 ft entry, 300 Feet Per Minute, 1200 sq-ft, 8ft height
Open Walls

60

120

Conservative outside ventilation assumption, 0.02 MPH wind max
Patio

37

120

Conservative outside ventilation assumption, 0.02 MPH wind max
Outside Unblocked

60

120

Conservative outside ventilation assumption, 0.02 MPH wind max
Outside Courtyard

37

120

Conservative outside ventilation assumption, 0.02 MPH wind max
Outside Massive Crowds

0

4

Ventilation ineffective due to close distances and blockage from crowd

Mechanical Ventilation

The following is a procedure used to gather data and calculate the ACH in a facility using mechanical ventilation without using room size and anemometer measurements. This is called seat of the pants analysis but it is amazing how close the results will match results using tape measures for room sizes and an anemometer.

  1. Estimate the facility size. A good gauge to use is to look at the outside windows. Count the number of windows along the wall. Approximate the width of each window using 3 feet, 4 feet, or 6 feet. For walls where there are no windows visualize how many windows might be along the wall. For the height of a facility visualize how many people can be stacked until the ceiling is reached. Use 6 feet for each person. Alternatively think in terms of 10 foot sections stacked up.
  2. Count the number of ventilation vents. Look around the facility and find the ventilation vents. There may be different sized vents. Count the vents for each size vent. Label then Vent A, B, C etc. Next estimate the size of each vent. They are standard sizes. For homes they tend to be 6 X 12 inches but the openings are 3 X 9 inches. Think in terms of 3, 4, 6, and 12 inches wide and 12, 24, 36, and 48 inches long. Vents in ceiling tile tracks may be 4 X 48 inches.
  3. Look for things like ceiling fans and exhaust fans.
  4. Look for things like ceiling level UV-C lights or FAR UV-222 lights.
  5. Use your smart phone to save the data, send yourself an email with the data.
  6. If you feel air across your face the facility ventilation is not bad. In the calculations you can assume 100, 200, 300, 400 linear feet per minute per vent.
  7. If you don't feel air across your face you can assume 0, 50, 150, and 200 linear feet per minute.
  8. Obviously a facility owner or operator can use tools (ruler, tape measure, and anemometer) to make the measurements.

When you get home or to the office you can make the calculations. The following steps are used to make the calculations.

The following is an example to estimate the facility size and calculate the square feet and cubic feet. [facility-calculations] spreadsheet.

The CAB has its own mechanism to capture the facility data and calculate the ACH. It is available at Add A New Facility. There is a link on the form near the ACH entry areas called ACH Calculations.

Item

Data and
Calculations

Comment
Room length ft

64

16 4 foot windows 16 X 4
Room width ft

30

10 3 foot windows 10 X 3
.

Room sq feet

1920

sq feet = Length x Width
.

.

.
Room height ft

20

Estimated as 2 10 foot sections
.

.

.
Room cubic feet

38400

cubic feet = sq feet X height ft

The following is an example to calculate the ACH in a facility.

Item vent type A vent type B Comments
Vent length inches

3

12

Vent width inches

36

36

number of vents

6

9

Vent sq inches

648

3888

Vent sq inches = Length X Width inches
Vent sq feet

4.5

27

Vent sq feet = Vent sq inches / 144
air ft per min
(measured or estimated)

200

200

measured air ft per min comes from an anemometer measurement.
estimated air ft per min comes from the general rules:
  • If you feel air across your face you can assume 100, 200, 300 linear feet per minute per vent.
  • If you don't feel air across your face you can assume 0, 50, 150, and 200 linear feet per minute
cubic feet per min CFM

900

5400

CFM = Vent sq feet X air ft per min
cubic feet per hour CFH

54000

324000

CFH = CFM * 60
total CFH

-

378000

total CFH = add all the vent types CFH
.

.

.

.
ACH

9.8

ACH = total CFH / Facility cubic feet from previous table that calculated facility size. Do this for the min, max, and avg ACH.

Use the [facility-calculations] spreadsheet or the CAB ACH Calculations to make calculations.

Based on the data you collected and the calculations performed you should have all the data to make a facility entry. Use the comments area to add all your observations and data that you collected. The comments will appear in the Clean Air Building certificate.

The following tables list differnt vent, diffuser, and return grill sizes that can be used to estimate the size of the vents in a facility.

Vent, Diffuser, and Return Grill Sizes

When looking at a vent, diffuser, or return grill the outside size is larger than the actual vent opening. The following tables identify the vent, diffuser, and return grill openings. The vent, diffuser, and return grill size exceeds the opening on each side by 1 inch. So a vent that looks like and measures from  the outside as a 4 x 12 inch vent is really a 2 x 10 inch vent because that is the size of the opening. Also, the opening might be partially blocked around the perimeter and with reinforced strips down the middle. So a 4 x 10 vent might scale down to a 3 x 8 vent opening.

Vents

If applicable pick a vent size and enter it in the ACH Calculations table (Length and Width). Keep in mind the FPM level for when the Vent Air FPM is requested.

Vent Sizes

Vent Size
(in)

Vent Size
(in)

Vent Size
(in)

Vent Size
(in)

Vent Size
(in)

Vent Size
(in)

2 x 10
2 x 12
2 x 14
2 x 48

3 x 8
3 x 10
3 x 12
3 x 14
3 x 48

4 x 8
4 x 10
4 x 12
4 x 14
4 x 48

6 x 8
6 x 10
6 x 12

8 x 10
8 x 12
8 x 14

8 x 8
10 x 10
12 x 12
14 x 14
18 x 18
24 x 24

Note: Most likely near 350 FPM

Diffusers

The following tables are vent diffusers. and they show sizes and typical airflow. When the CFM is divided by the area of the vent this provides the FPM.

This can be used as a guide when making observations or actually measuring the vent FPM.

The FPM numbers in the table are the upper limit and the airflow will Most likely be near 350 FPM.

If applicable pick a Diffuser size and enter the neck diameter in the ACH Calculations table (Width / Diameter column). Keep in mind the FPM level for when the Vent Air FPM is requested.

4-Way Diffuser Sizes

Airflow (cfm)

Diffuser Size

Neck Size (in)

Airflow (FPM)

150

2 ft x 2 ft

8

430

200

2 ft x 2 ft

8

573

250

2 ft x 2 ft

10

458

300

2 ft x 2 ft

10

550

350

2 ft x 2 ft

12

445

400

2 ft x 2 ft

12

509

450

2 ft x 2 ft

14

421

500

2 ft x 2 ft

14

468

Note: Most likely near 350 FPM

Round Diffusers

Neck Sizes are: 8, 10, 12, 14 inches

Note: Most likely near 350 FPM

Linear Diffuser Sizes

Airflow (cfm)

Diffuser Size

Neck Size (in)

Airflow (FPM)

50

1-slot, 2 ft

6

255

100

2-slot, 2 ft

8

286

150

2-slot, 4 ft

8

430

200

2-slot, 4 ft

10

367

250

3-slot, 4 ft

8

716

300

3-slot, 4 ft

10

550

350

4-slot, 4 ft

10

641

400

4-slot, 4 ft

12

509

Note 1: 50mm/slot or 1.95 inches/slot
Note 2: Most likely near 350 FPM

The following table can be used to deal will mixed sized vents in a room.

Neck Size (in)

Area sq-in

6

28

8

50

10

79

12

113

Return Grills

You can measure the ventilation level using the vents / diffusers or return grills. The return grills suck in the air, send it through the system, and then expels the air out the vents / diffusers. Measuring the return grills will provide an indication of the percent of outside air being introduced into the space. It is also a good sanity check of the vent diffuser measurements.

The following are return air grills. The return air grills are similar in size to vents. The data in the following tables are based on 350 linear feet per minute (FPM) as measured at the grill.

If applicable pick a vent size and enter it in the ACH Calculations table (Length and Width).

Horizontal Return Air Grilles

Grille Area (sq.in)

Grille Size (in)

Airflow (cfm)

Airflow (FPM)

24

4 x 6

58

348

48

4 x 12

117

351

60

6 x 10

146

350 all others

180

6 x 30

438

128

8 x 16

311

144

8 x 18

350

192

8 x 24

467

240

8 x 30

583

256

8 x 32

622

200

10 x 20

486

220

10 x 22

535

240

10 x 24

583

300

10 x 30

729

216

12 x 18

525

240

12 x 20

583

288

12 x 24

700

360

12 x 30

875

238

14 x 17

578

280

14 x 20

681

350

14 x 25

851

364

14 x 26

885

288

16 x 18

700

320

16 x 20

778

400

16 x 25

972

416

16 x 26

1011

432

18 x 24

1050

468

18 x 26

1138

540

18 x 30

1313

576

18 x 32

1400

480

20 x 24

1167

500

20 x 25

1215

600

20 x 30

1458

Note: Most likely near 350 FPM

Square Return Air Grilles

Grille Area (sq.in)

Grille Size (in)

Airflow (cfm)

Airflow (FPM)

36

6 x 6

88

352

64

8 x 8

156

351

100

10 x 10

243

350 all others

144

12 x 12

350

196

14 x 14

476

256

16 x 16

622

324

18 x 18

788

400

20 x 20

972

484

22 x 22

1176

576

24 x 24

1400

676

26 x 26

1643

900

30 x 30

2188

Note: Most likely near 350 FPM

Verticle Return Air Grilles

Grille Area (sq.in)

Grille Size (in)

Airflow (cfm)

Airflow (FPM)

48

12 x 4

117

351

72

12 x 6

175

350 all others

120

12 x 10

292

84

14 x 6

204

112

14 x 8

272

140

14 x 10

340

96

16 x 6

233

128

16 x 8

311

192

16 x 12

467

180

18 x 10

438

216

18 x 12

525

252

18 x 14

613

160

20 x 8

389

200

20 x 10

486

240

20 x 12

583

280

20 x 14

681

320

20 x 16

778

360

20 x 18

875

176

22 x 8

428

220

22 x 10

535

96

24 x 4

233

144

24 x 6

350

192

24 x 8

467

288

24 x 12

700

336

24 x 14

817

384

24 x 16

922

432

24 x 18

1050

364

26 x 14

885

416

26 x 16

1011

468

26 x 18

1138

224

28 x 8

544

644

28 x 23

1565

180

30 x 6

438

240

30 x 8

583

300

30 x 10

729

360

30 x 12

875

420

30 x 14

1021

480

30 x 16

1167

128

32 x 4

311

256

32 x 8

622

384

32 x 12

933

640

32 x 20

1556

272

34 x 8

661

360

36 x 10

875

432

36 x 12

1050

504

36 x 14

1225

608

38 x 16

1478

800

40 x 20

1944

Note: Most likely near 350 FPM


.

How to Calculate Room ACH

There are 2 approaches to calculate Room ACH.

The first approach is to use the: ACH Calculations Tool - ACT. When you arrive at the page just press the ACH Calculations button and start entering data. This is probably the easiest approach. You also have the option of adding the building into the open source database of buildings around the world.

The second approach is to use the following steps to calculate the ACH for each room. Some rooms have multiple vents. Make sure to measure all the vents in a room.

  1. Measure room Length, Width, and Height in feet
  2. Measure each Vent Length and Width in inches
  3. Measure each vent Linear Feet Per Minute (LFM) using anemometer (buy the lowest cost ~ $19)
  4. Example anemometer: https://www.amazon.com/Anemometer-Handheld-Detector-Temperature-Windsurfing/dp/B07ZJ38ZMX
  5. Use the following steps to calculate the ACH
  6. Vent Cubic Feet Per Minute (CFM) = Vent 1 Length * Vent Width * LFM  1 / 144
  7. Room Ventilation CFM = Vent 1 + Vent 2 + ...
  8. Room cu-ft = Room Length * Width * Height
  9. ACH = Room Ventilation CFM / Room cu-ft

Write it all down so that you don't get lost. Use a separate sheet of paper for each room. Don't try to make perfect measurements. Room shapes are odd and ventilation readings vary. Set the meter to read the Max rate and move it across the entire vent. These approximate readings are all that are needed to make reasonable assessments of the ACH levels.

Ventilation Test Procedure Performed By Volunteers

There is great resistance on the part of facility managers to perform ventilation measurements and disclose the ventilation rates in terms of ACH. Others still appear to be trying to determine how to proceed. The following procedure is offered to volunteers to gather ventilation data. This can be performed by parents, teachers, unions, residents, employees, owners, and others for schools, clubhouses, libraries, workplaces, buildings of all types, transportation vehicles of all types, and other spaces.

Staff - 3 people

  1. 1 scribe to write the data down and take notes
  2. 1 person taking the measurements
  3. 1 person as a second set of eyes and taking measurements when the other person gets tired
  4. Or alternatively you do it yourself, it is not that hard

Tools

  1. 1 anemometer - https://www.amazon.com/Anemometer-Handheld-Detector-Temperature-Windsurfing/dp/B07ZJ38ZMX ($17)
  2. 2 metal broom sticks from the dollar store and 2 lawn light stakes to join sticks ($4)
  3. 1 selfie stick to hold anemometer ($1)
  4. 1 Computer to record the data and produce the test results
  5. ACH Calculations Tool (ACT) tools to perform the calculations
  6. Clean Air Buildings (CAB) places the data in the public database for comparison with other facilities

Calculations

You can use the ACH Calculations Tool (ACT) or perform the calculations yourself as follows:

Reference Data

  1. Room Cubic Feet (cu-ft) = Length X Width X Height
  2. Vent Size in Square Inches (sq-in) = Length X Width
  3. Vent Size in Square Feet (sq-ft) = (Length/12) X (Width/12)
  4. Anemometer Feet Per Minute (FPM) = Measured from Anemometer
  5. Cubic Feet Per Minute  (CFM) = Anemometer Feet Per Minute X Vent Size In Square Feet
  6. Cubic Feet Per Hour (CFH) = Cubic Feet Per Minute X 60
  7. ACH = Cubic Feet Per Hour / Room Cubic Feet
  8. or ACH = CFH / Room cu-ft
  9. or ACH = Anemometer Feet Per Minute X 60 X (Vent Size in Square Inches / 144) / Room Cubic Feet

Test Procedure

Cubical Area

  1. Measure office cubical space (L W H)
  2. Walk each isle and look for vents per the facility drawing if it exists, if no drawing just look for vents
  3. Measure each vent linear feet per minute (FPM) using MAX setting
  4. Measure the size of each vent (should be all the same)
  5. Record the data

Rooms

  1. Find all rooms with doors
  2. Name each room
  3. Measure each room space (L W H)
  4. Open the door
  5. Measure each vent linear feet per minute (FPM) using MAX setting
  6. Measure the size of each vent
  7. Record the data

Hall

  1. Measure space (L W H)
  2. Measure each vent linear feet per minute (FPM) using MAX setting
  3. Measure the size of each vent
  4. Record the data

Bathrooms and Snack Room

  1. Measure space (L W H)
  2. Measure each vent linear feet per minute (FPM) using MAX setting
  3. Measure the size of each vent
  4. Record the data

General Guidelines

  1. Look for vents with no ventilation
  2. Look for vents with drastically lower ventilation rates than nearby vents
  3. Look for spaces that appear to have missing vents
  4. Look for inconsistencies
  5. If exhaust vents are found measure them, they will be used to check for consistency with outlet vents

Embeded video link https://www.youtube.com/watch?v=HlneLDi9r54 (video on how to calculate air changes per hour)

If you can't measure the ventilation rates from the vents then just count the number of vents and use the guidelines at the start of this page to determine the ventilation rate from each vent. Pick the vent size and estimate the ventilation rate. If you feel air across your face the facility ventilation is not bad. In the calculations you can assume 100, 200, 300, 400 linear feet per minute per vent. If you don't feel air across your face you can assume 0, 50, 150, and 200 linear feet per minute. See section Finding Facility Data.

The procedure and process is very simple. Do not be side tracked with irrelevant details that some may claim to stop the measurements. Just roll up your sleeves and do the work and then present it to the community.


Copyright © 2021 Cassbeth Inc. All Rights Reserved. Proprietary. This information can be only used for education, research, or news media organizations. Any other use of this information by any entity where there is a financial transaction such as for products or services by for profit, nonprofit, and government organizations must contact Cassbeth for release.