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OAR Box 1252 

Prepped by Candice Davis 

Document Number: 

51) ll-B-11 

Docket Number: 

A-90-22 

Printed 5/21/2008 11:46:01 AM Sheet 51 of 184 
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MEMORANDUM 

DATE: 

TO: 

FROM: 

SUBJECT: 

Ql-B-H 1 

November 25, 1991 

HON Project File 

Mae L. Thomas, Radian 

Interpretation of Louisiana Rule for Control 

Transfer Operations and the Computer Code of the Rule 

for the HON Framework 

The purpose of this memorandum is to present the 

interpretation of the Louisiana transfer rule and to explain 

computer coding the rule into the HON Framework. The baseline 

control requirements imposed by the State regulations represent 

the level of control in the absence of the HON and will be used 

in the impacts analysis. 

The Louisiana transfer rule applies to loading volatile 

organic compounds (VOC's) with a vapor pressure of 1.5 psia or 

more into tanks, trucks, or trailers. VOC's as defined by the 

Louisiana rule, are any organic compound which participates in 

atmospheric photochemical reactions. The Louisiana rule has a 

throughput cutoff of 40,000 gal/day averaged over 30 days for 

facilities built before May 20, 1979 and 20,000 gal/day averaged 

over 30 days for facilities built after May 20, 1979. A 

throughput cut-off of 40,000 gal/day for all facilities was used 

in the computer coding of this rule because the age of the 

facilities was not known. 

The control required by this rule is a vapor return line to 

the dispensing vessel (vapor balancing) or a disposal system with 

a destructive/removal efficiency of 90 percent. A 90 percent 

efficient vapor recovery device was used in computer coding the 

requirement of this rule. 

In computer coding the Louisiana rule, a few additional 

assumptions were made. It was assumed that chemicals with vapor 

pressures greater than 14.7 psia will be transferred under 

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pressure and therefore will not have any emissions to control. 

Also, the assumption was made that the 40,000 gal/day throughput 

cut-off applied to one chemical being transferred via a given 

vehicle type (i.e., tank truck or tank car). Therefore, for a 

facility to meet the control criterion, the throughput of a 

chemical transferred by a given vehicle type would have to exceed 

4 0,000 gal/day. This assumption results in fewer facilities 

requiring State control at baseline than if it had been assumed 

the 40,000 gal/day cutoff applied to the combination of all 

chemicals and all vehicle types loaded at the facility. As a 

result of this assumption, the analysis of the impacts of the HON 

regulatory options shows that more facilities are uncontrolled at 

baseline and will be required by the HON to add controls, giving 

higher HON cost and higher HON emission reduction estimates. A 

sensitivity analysis performed on this assumption showed that 

17 percent more racks (nationwide) would require control at 

baseline if it had been assumed, for all state regulations 

analyzed, that the throughput applied to all regulated chemicals 

transferred at the facility.1 However, this assumption did not 

affect the MACT floor determination. 

In order to determine the baseline control requirement, the 

HON transfer data base TR_ASSG.DBF is accessed to obtain the 

actual tank truck (field: TT_TP) and tank car annual throughput 

(field: RC_TP). The HON transfer program currently accesses the 

field and carries the data in the memory variables: M_TOT_TTTP 

and M_TOT_RCTP. Depending on the vehicle type, one of these is 

then assigned as the throughput. Throughput is in units of 

thousands of gallons per year. Therefore, it must be converted 

to thousands of gallons per day to be compared with the Louisiana 

throughput cut-off of 40 thousand gallons/day. To perform the 

conversion, the throughput is divided by 365 multiplied by the 

capacity utilization factor (HON_CHEM->US_CAPUTIL). The 

assumption is that facilities transfer every day they produce. 

Multiplying the number of days in a year by the capacity 

utilization factor estimates the number of days in a year the 

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facility transfers product. The capacity utilization factor 

represents the difference between the amount of product produced 

and the facility's total capacity to produce. This assumption 

may underestimate the level of baseline control and result in 

overestimating costs and emission reductions attributable to the 

HON. The computer coding reads as follows: 

IF M_VECHTYPE = 'TT' 

M_TOT_TP = M_TOT_TTTP/(365 * HON_CHEM->US_CAPUTIL) 

ELSE 

M_TOT_TP = M_T0T_RCTP/(365 * HON_CHEM->US_CAPUTIL) 

Once the throughput data have been collected, the data were 

compared to the Louisiana requirements and a baseline percent 

reduction and a baseline control device are assigned. The 

computer coding to do the comparing and assigning reads as 

follows: 

IF M_TOT_TP>=40 .AND. M_VAP_PR>=77.55 .AND. M_VAP_PR<760 

M_REDUCT =0.90 

M_CTLDEV = 'VAPOR RECOVERY' 

ELSE 

M_REDUCT = 1 

M_CTLDEV = 'NONE' 

ENDIF 

For those chemicals transferring at 40,000 gal/day or 

greater and having a vapor pressure greater than 1.5 psia 

(77.66 mmHg) and less than 14.7 psia (760 mmHg), the Louisiana 

control requirement of vapor recovery and a reduction of 0.90 

(90 percent) was assigned. No control device and a reduction of 

1 are assigned for those chemicals not within the vapor pressure 

range or within the throughput range. The reduction of 1 does 

not indicate that 100 percent of emissions are reduced. Rather, 

it is used by the computer code as a flag meaning no baseline or 

State control. 

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REFERENCES 

1. Thomas, M.L., Radian Corporation, to HON Project File, 

January 24, 1992. Sensitivity Analysis of the Minimum 

Throughput Assumption in the Interpretation of the State 

Regulations and the Benzene NESHAP for Transfer Loading 

Operations. 

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