Stack height

Effective Stack Height Plume Rise, US EPA Air Pollution Training Institute Pub. SP.406, with Chapts. D, E, and G by G. A. Briggs and Chapt. H by D. 

HCl and Cl Emission Limits. Hydrochloric acid and chlorine must also meet emission limits for an adjusted stack height. 

Z9 = plate stack height in scaled-up column df = diameter of pilot column df9 = diameter of scaled up column SPM = reciprocating speed of pilot column SPMo = reciprocating speed of scaled-up column... 

The effective stack height (equivalent to the effective height of the emission) is the sum of the actual stack height, the plume rise due to the exhaust velocity (momentum) of the issuing gases, and the buoyancy rise, which is a function of the temperature of the gases being emitted and the atmospheric conditions. 

The lowering below the stack top of pieces of the plume by the vortices shed downwind of the stack is simulated by using a value h in place of the physical stack height h. This is somewhat less than the physical height when the stack gas exit velocity is less than 1.5 times the wind speed u,... 

The final effective plume height H, in m, is stack height plus plume rise. Where buoyancy dominates, the horizontal distance Xf from the stack to where the final plume rise occurs is assumed to be at 3.5 , where x is the horizontal distance, in km, at which atmospheric turbulence begins to dominate entrainment. 

Under stable conditions, the lowest value of Eq. (20- 6a) or (20-7) is usually taken as the effective stack height. 

Fig. 20-2. Ratio of second highest 24-hr estimated concentrations from the CRSTER model (47) to measured concentrations as a function of the excess of receptor elevation over stack base evaluation A relative to the stack height h. Names with each symbol are power plants. Source From Turner and Irwin (48).

A version of the Gifford-Hanna model was evaluated (50) using 1969 data for 113 monitoring stahons for particulate matter and 75 stations for SO2 in the New York metropolitan area. This version differed from Eq. (20-19) in considering major point source contributions and the stack height of emission release. This model produced results (Table 20-2) comparable to those of the much more complicated COM model (51). 

PAN fibers develop a structure with little point-to-point relationship between atoms in neighboring basal planes. This structure is labeled the turbostratic configuration and is characterized by interplanar spacing values greater than 0.344 nm. The crystallite size in the direction normal to the basal planes, or stack height (L, ), in turbostratic graphite is typically less than 5 nm. 

Sprinklers Maintain sprinkler systems Institute alterations if building is modified, use changes etc. Observe use specifications, e.g. for stack heights, fire loading... 

Split-up stocks into manageable lots, e.g. with reference to fire loading/spillage control. Limit stack heights generally... 

Limit stack heights, e.g. 4.5 m for 200 litres drums., 5 m high for drums stored on end or 4 m high on pallets, 4 m high for drums on their sides. 

H = effective stack height Oy = diffusion coefficient in the y-direction, m = diffusion coefficient in the z-direction, m... 

Since U is a function of z, some mean value must be used. The appropriate value is the mean through the plume. However, the time-averaged wind speed at the stack height is commonly used. Often, even this value may not be known, in which case an estimate must be made. This estimate could be based on an assumed power law velocity profile such as ... 

Stone-Clark Ah = (104.2 + 0.17hp)Qh /U where hp = physical stack height (m) Modification of Lucas-Moore expression, takes into account effect of physical stack... 

SIMPLE TERRAIN INPUTS SOURCE TYPE EMISSION RATE (G/S) FLARE STACK HEIGHT (H) TOT HEAT RLS (CAL/S) RECEPTOR HEIGHT (M) UR6AN/RURAL OPTION EFF RELEASE HEIGHT (H) BUILDING HEIGHT (M)... 

For u, a value of one-half the stack height critical wind speed is used, but not greater than 10 m/s and not less than 1 m/s. Thus, the calculation of Xc is linked to the determination of a critical wind speed. The concentration, Xc is assumed to be uniform within the cavity. 

The values of u and A0/AZ are based on assumed conditions of stability class F and stack height wind speed of 2.5 m/s for the stable layer above the inversion. The value of hj incorporates the effect of buoyancy induced dispersion on a/, however, elevated terrain effects are igndred. The equation above is solved by iteration, starting from an initial guess of x , = 5,000 m. The maximum ground-level concentration due to inversion break-up fumigation, Xf, is calculated from ... 

Shoreline Fumigation - For rural sources within 3000 m of a large body of water, maximum shoreline fumigation concentrations can be estimated by SCREEN. A stable onshore flow is assumed with stability class F (A0/AZ = 0.035 K/m) and stack height wind speed of 2.5 m/s. Similar to the inversion break-up fumigation case, the maximum ground-level shoreline fumigation concentration is assumed to occur where the top of the stable... 

---