3003 W CASINO RD PAINT HANGAR BOUNDARIES 2023-07-20

j * ari Geminus Boeing Project Contract No.EVE-16-2929 Technology Development CEI Project No. 160731 changed, but the overall airflow & % of LEL concentrations in the hangar will be substantially the same. • The actual location of the wing, tail and empennage stands will locally affect the airflow & % of LEL distribution, but should not significantly affect the overall % of LEL concentrations. Every effort has been made to accurately locate these hangar entities relative to the aircraft and the paint hangar. 2.2.1.4 Geometry - Stacker Cranes and Paint Platforms The high and low bay stacker cranes (paint platforms) were modeled by Coffman Engineers Inc. and simplified to have elements that would substantially affect the airflow during the painting process. These elements included models of the crane rails, trolley rails, and trolley features themselves. The following assumptions are made regarding the stacker cranes: • The stacker cranes are placed along the length of the aircraft in a manner that would create an overspray "cloud" with the largest distribution along the length of the aircraft (see Figure 11) [4]. • The stacker cranes are placed about halfway between the window line and crown of the aircraft. Boeing has determined from experience that painting from this position typically creates the largest overspray "cloud". The above assumptions impose the following limitations on the model: • If the plastic sheet is removed from underneath the stacker platform the airflow will not be blocked. This should provide better overspray removal by the supply air, thus the blocked assumption is more conservative. • If the stacker cranes are moved further from the aircraft surface than modeled the interaction with the high velocity supply air is further reduced and will provide a more efficient removal of any over-spray. A smaller distance to the aircraft surface, which is not likely than the 9 inches used in the models, would produce a larger airflow blockage and could significantly modify the overspray cloud locally. It is not expected that the overall % of LEL concentrations away from the aircraft would be significantly affected. • If the stacker cranes are positioned closely together along the length of the aircraft fuselage and remain close for a long period of time, the local % of LEL concentrations may significantly increase — and may approximately double due to 2x the overspray generation locally. However, it is understood that during the normal paint process, the paint platforms separate from each other rapidly and the painters are not near each other on adjacent platforms for a significant portion of time. 2.2.2 Ventilation The supply and exhaust ventilation of the original 45-04 hangar that is used in the CFD model was based on measured air supply and exhaust mass flow (CFM) distributions during Nominal Paint Mode operations (see measurements taken in [5]) that together with nominal building air leakages produce a slight (-0.01 to 0.03" H2O as per Boeing [6]) negative building pressure. 11