FIELD SURVEY OF TRUNK LINE HEATING GAS LEAKS IN COMMERCIAL BROILER HOUSES

A field survey was conducted on 23 farms (101 broiler houses ranging in age from new to 33 years old) in central and south Alabama to evaluate the presence of gas leaks on the high-pressure trunk line. Gas trunk lines usually run on the outside of poultry houses exposing them to temperature fluctuations that cause expansion and contraction of the rigid steel piping. Each threaded connection has the potential to leak. A soap solution in a hand sprayer was used to spray each connection and evaluate the presence of a leak through bubble formation. Leaking fittings were evaluated as percent- age of total fittings to account for variation across houses. Pearson correlation matrices were used to determine correlations of house age and floor area on total number of fittings and percentage of leaking fittings. Total number of fittings ranged from 36 to 170 per house and was strongly correlated to floor area [r(99)=0.70, p < 0.0001]. Larger floor areas require more heaters and longer piping systems. Percentage leaking fittings ranged from minimum of 0% to maximum of 32% per house and was not correlated with either house age [r(99)=0.03, p=0.74] or floor area [r(99)=0.05, p=0.65] for the houses surveyed. Leaks seemed to be more about regulator quality and installation craftsmanship with variation across farms and houses within farms. Of houses surveyed, the overall mean leaking fittings was 6.9% & PLUSMN; 0.6%. Poultry producers should get written verification from the gas line contractor/installer that newly constructed houses are free of leaks before operating the farm. It would be useful for poultry producers to check for leaks annually to verify system integrity and to monitor any developing leaks.