980 CMR 10.03 - Performance Standards for Determining Site Sizes

(1) Thermal Radiation Protection.

(a) The area of the property must be sufficiently large to provide a thermal protection zone.

(b) Within the protection zone, the dike constructed to impound the LNG may not be located closer to targets Usted in 980 CMR 10.03(l)(d) than distance "d".

(c) The protection distance "d" is measured as shown in FIGURE 4 along the line (PT) in a vertical plane defined by the points (T) and (D), where

(T) is a point at the top of the target;

(D) is a point closest to (T) on the top inside edge of the dike;

(PD) is a line in the vertical plane which intersects (D) at an angle of 45° above horizontal;

(w) is the inside distance across the top of the impounding space measured normal to (PD); and

(P) is located where (PT) and (PD) intersect at an angle of 90° or where (PD) equals 3 (w), whichever results in the shortest length of (PD).

F. GURE 4

SEE TEXT

(d) The length of a protection distance in feet may not be less than the distance "d" determined in accordance with the following formula for the target concerned, when "A" equals inside area in square feet measured across the top of the impounding space:

TARGET	PROTECTION DISTANCE
1. Any point in an area outside the property line which is not zoned for industrial use.	d = 3.6 (A)0.5
2. Any point in an area outside the property line which is zoned for industrial use.	d = 2(A)0.5

(e) For any facility which depends upon surrounding industrially zoned land for compliance as provided in 980 CMR 10.03(l)(d) the applicant must conduct a safety consultation session with the local planning board and with each owner of land in the affected portions of the suiTOunding industrial zone. Prior to conducting safety consultations, the applicant must confer with the Department of Public Utilities on the scope and content of the safety consultation sessions. The applicant must give notice to the Department of Public Utilities that such consultations have been completed prior to the transfer of any LNG to the site or processing of LNG at the site.

(f) The method described in 980 CMR 10.03(c) and 10.03(d) shall be the accepted method of calculation of the thermal protection distance. Any interested party may request a rulemaking procedure to qualify an additional method of calculation. No facility may be evaluated using a new method of calculation unless the method has been submitted to the Council six months prior to the filing of the forecast containing the facility proposal, and unless that method is approved and accepted by the Council prior to the filing of the forecast containing the facility proposal.

(2) Vapor Dispersion Exclusion Zone.

(a) Zone Requirement. Each LNG facility shall be designed to prevent flammable vapor from a design spill as defined in 980 CMR 10.03(2)(b) from crossing the property line. The boundary of the vapor dispersion exclusion zone will be determined by the minimum exclusion distance computed in accordance with this section. The vapor dispersion exclusion zone will be determined by a standard at the property line of an average gas to air concentration of no more than 2.0 percent. The boundary or estimated dispersion distance (D) is measured radially from the inside edge of the impounding system along the ground contour to the vapor dispersion zone boundary.

(b) Design Accidents for the Calculation of Dispersion Distance (D) hi computing dispersion distance (D) under 980 CMR 10.03(2)(d), the following applies:

1. The value of (Dj) is the lesser of the values resulting from the following vapor generation conditions:

a. Vapor generation rate equals the maximum constant rate of discharge from failed transfer piping having the greatest overall flow capacity.

b. Vapor generation from sudden contact of LNG with 100% of the impounding system floor area and 50% of all liquid impounding surfaces which the liquid could contact, including the walls and roof of the component served, plus flash vaporization from the maximum constant rate of discharge from failed transfer piping having the greatest overall flow capacity.

2. The value of (Dj) is based on the following applicable conditions:

a. For all classes of impounding a sudden total spill of the maximum contents of the largest component served, with vapor generation resulting from liquid contact with surfaces of the impounding system and outer component surfaces exposed to the final static fluid configuration and flash vaporization from the contents of the component served.

3. The distance (D) equals the greater of (D,) or (Dj).

(c) Vapor Flow Rate.

1. The maximum time (t) required for the release of liquid from a component served in a sudden total spill is determined in accordance with the following equation:

(t) = 9(h/G)^0.5

where (t) is the time, (h) is the difference between the maximum height in feet of the contained liquid and the equilibrium height of liquid when impounded, and (G) is the acceleration of gravity.

2. Impounding and other surfaces which may be contacted by LNG under conditions described in 980 CMR 10.03(2)(b) l. and 10.03(2)(b)2. may be insulated. The heat transfer value and application technique of the proposed insulating material must be satisfactory to the Department of Public Utilities. The boiling rate of LNG on which (D) is based, is determined by multiplying .9 times the weighted average value of (KPC)0.5 determined from eight representative experimental tests on the contact surfaces in the impounding space, where

K = thermal conductivity in (BTU/(HR) (ft) (F°)),

P = density in (1 lb/ft³), and

C = heat capacity in (BTU/(lb) (F°)). The test conditions should vary in terms of the spills' elevation, separate velocity, and quantity. 3. Dispersion distance (D) is determined on the basis that vapor detention space does not exceed:

a. For conditions described in 980 CMR 10.03(2)(b) l.a. of the preceding section, all space provided for liquid impoundment and vapor detention outside the component served; and

b. For conditions described in 980 CMR 10.03(2)(b)2.a. all space provided for liquid impoundment and vapor detention outside the component served less the volume of the liquid that would have entered the impounding space when generating vapor escapes the vapor detention barriers, assuming liquid to be entering the impounding space outside the component served at a constant rate over the time period prescribed by 980 CMR 10.03(2)(c) l.

(d) Calculationof Vapor Dispersion Distance. The boundary or estimated dispersion distance (D) must be calculated in accordance with the applicable parts of Appendices A, B, and C of the publication, "Evaluation of LNG Vapor Control Methods" (American Gas Association, Arlington, VA., 1974), subject to the following parameters and other requirements of 980 CMR 10.03:

1. Average gas concentration in air is 2.0% by volume.

2. Wind speed (w) is 5.0 miles per hour.

3. Source height (H) is zero.

4. Source width (L) is A^0.5, where A is the inside area measured across the top of the impounding space, as in 10.03(l)(d).

5. The Gifford-Pasquill atmospheric stability category is F (moderately stable).

6. The temperature of the impounding and storage vessel surface is 47°C.

(e) Additional Methods of Calculation. The method reference in 980 CMR 10.03(2)(d) shall be the accepted method of calculation of the vapor dispersion distance. Any interested party may request a rulemaking procedure to qualify an additional method of calculation for vapor dispersion. No facility may be evaluated using a new method of calculation unless that method has been submitted to the Council six months prior to the filing of the forecast containing the facility proposal, and unless that method is approved and accepted by the Council prior to the filing of the forecast containing the facility proposal.

Notes

980 CMR 10.03