for the Health Risk Tool (HRT) (version 1.5)
for the Health Risk Tool (HRT) (version 1.5)
If you're seeking help in using the Health Risk Tool, you've come to the right place! To answer your questions as quickly as possible, this help file has been organized into the following sections:
Additionally, there are programming notes available for anyone interested.
Inputs
Internal combustion equipment includes internal combustion engines. External combustion equipment includes boilers, ovens, furnaces, dryers, absorption chillers, etc. Selection of either one of these buttons will display the range of equipment sizes that are available.
For external combustion equipment, select the heat input rating (MMBtu/hr); for internal combustion equipment, select horsepower. Choose the size that is closest to the specifications of your equipment. If the exact size of your equipment is not on the list, choose the next largest equipment size in order to determine the most conservative impact due to air toxics.
At maximum operation, will the equipment operate more or less than 12 hours per day? Check the appropriate box. This limit is a permit limit, not just expected maximum.
Input the maximum number of hours per year that the equipment will be operating. 8760 hours represents one full year. Again, this would be a permit-specified limit.
If you selected less than 12 hours per day and input more than 4380 hours (1/2 of 8760) you will get an error message.
For an internal combustion engine, T-BACT is the standard catalytic converter that would be required on all engines. For external combustion, T-BACT is the use of natural gas as a fuel.
If you have information on actual control efficiency of air toxics, input it here.
The default value here is 70% for internal combustion engines. For external combustion, the default control efficiency is zero.
Select the city nearest the installed equipment. This ensures that the meteorological data used most closely matches that of the equipment site. These cities are the locations of meteorology stations. See Appendix E for the AQMD map that shows the location of the meteorological monitoring stations.
Select the range of dates during which the permit application was deemed complete. Rule 1401 has changed over time and different risk factors apply depending on the date.
Measure this distance from the point where the exhaust exits the stack to the nearest point on the property line of the nearest business, home, school, etc. Be sure to select the correct units of measure. The distance to the nearest business or industrial facility is used for the commercial risk calculation. The distance to the nearest home, school, hospital, day-care center, or other sensitive receptor is used to calculate the non-commercial risk.
Outputs
If T-BACT controls are used, the threshold MICR is 1.0E-5 (10 in one million). If T-BACT controls are not used, the threshold MICR is 1.0E-6 (1 in one million).
This value is an estimate of the risk that a person will contract cancer because of that single emission source.
If the calculated MICR exceeds the threshold MICR, the answer is "yes." If the calculated MICR is lower than the threshold MICR, the answer is "no." If the MICR exceeds 1.0E-5, then no permit will be allowed for this equipment.
If the MICR is below 1.0E-6 (one in one million), then no public notice is required. If the MICR is between 1.0E-6 and 1.0E-5 (10 in one million), then public notice may be required, unless you can demonstrate that the facility-wide MICR is less than 1.0E-5. If the MICR exceeds 1.0E-5, no permit will be allowed, so the public notice question is not applicable.
This index is the non-cancer health risk due to short term (1 hour) exposure to Toxic Air Contaminants (TAC). The total risk is the sum of the acute risk impact of each TAC on their associated target organs. The maximum HIA out of all the target organs is presented as the result here. HIA cannot exceed 1.0.
This index is the non-cancer health risk due to long term exposure to Toxic Air Contaminants. The total risk is the sum of the chronic risk impact of each TAC on their associated target organs. The maximum HIC out of all the target organs is presented as the result here. HIC cannot exceed 1.0.
If the value of either HIA or HIC exceeds 1.0, the answer to this question is "yes." Otherwise, the answer is "no."
Calculate
When all inputs are entered, clicking this button calculates the results.
Refresh
Clicking this button clears the inputs and outputs and gives you a fresh screen.
Save
You may save your inputs by clicking this button. You may name this project and recall it later.
Delete
If you wish to delete a saved project, select the project name and click this button.
Help
Clicking this button opens the Help feature.
Exit
When you have completed your analysis, click this button to exit the program. Click "Close Full Screen." This removes the input screen and gives you access to the calculation and data spreadsheet tables. You may view details of the calculation that you have just performed. If you wish to restart the program, go to the Calculation sheet and click the Restart RiskWorks button. You may exit Excel by selecting Exit from the File menu.
External Combustion Default Consumption Rates
(back)|
|
|
|
|
(MMBtu/hour) 2 |
2000 |
.002 |
|
5 |
5000 |
.005 |
|
10 |
10,000 |
.01 |
|
20 |
20,000 |
.02 |
|
40 |
40,000 |
.04 |
|
50 |
50,000 |
.05 |
|
75 |
75,000 |
.075 |
Internal Combustion Default Consumption Rates
(back)|
Unit Size (BHP) |
Maximum Consumption Rate (cf/hour) |
Maximum Consumption Rate (MMcf/hour) |
|
50 |
500 |
.005 |
|
200 |
1732 |
.01732 |
|
350 |
2851 |
.02851 |
|
550 |
4482 |
.04482 |
Understanding the Types of Equipment
Health Risk Tool can analyze natural gas-fired internal or external combustion equipment. Internal combustion equipment includes internal combustion engines. External combustion equipment includes boilers, ovens, furnaces, dryers, absorption chillers, etc. The size range for each type of equipment is as follows:|
External combustion equipment: |
2 MMBTU/hour to 75 MMBTU/hour |
| Internal combustion engines: | 50 bhp to 550 bhp |
Choosing the Correct Equipment Size
If the size of your equipment is not shown in the list, choose the next largest equipment size in order to determine the impact of air toxics. For example, if the equipment to be screened is a boiler (an external combustion device) rated at 15 MMBTU/hour, you are presented with a limited number of equipment size choices (see Figure 3): Figure 3
Since a choice of 15 MMBTU/hour is not available, the choice for equipment size would be the next largest equipment size which turns out to be 20 MMBTU/hour.
Dealing with More Than One Piece of Equipment
To calculate the health risk from more than one piece of equipment, simply run each case separately and add the resultant health risk values.Note - the password for protected sheets in Health Risk Tool is "YorkeEngr" (case sensitive).