Mortars shall be positioned and discharged as follows:
- Mortars shall not be set up during night hours (between sunset and sunrise).
- Mortars shall be of sufficient strength and shall be arranged and positioned so that the shells may be safely discharged.
- Mortars shall be placed in as near a vertical position as possible. Mortars and other devices used to discharge fireworks shall be installed in accordance with NFPA 1123 and shall be positioned such that the shells are projected in a direction that ensures that they combust, deflagrate or detonate above the fallout area and all unexploded fireworks fall into the fallout area. Under no circumstances shall mortars be angled toward the viewing area.
- Mortars shall be of sufficient length to cause aerial shells to be projected to safe heights.
- Mortars shall be placed in sand-filled steel drums or heavy plastic drums no less than 32 gallons (121 L) in capacity. Wood racks or troughs filled with sand may also be used in lieu of drums for firing barrages or finales.
- Except for mortars placed in wood racks, mortars shall be buried to a depth of between two-thirds to three-quarters of their length.
- Except for mortars placed in wood racks and as may otherwise be provided in this section, mortars shall be separated from adjacent mortars by a distance of at least 2 inches (51 mm) or the diameter of the larger mortar, whichever is greater.
- Except as otherwise provided in this section, there shall be a separation distance of at least 2 inches (51 mm) or one-half of the diameter of the mortar, whichever is greater, between the mortar and the wall of the drum or trough.
- Prior to placement, mortars shall be inspected for defects, such as dents, bent ends, damaged interiors and damaged plugs. Defective mortars shall not be used. Any scale found on the inside surface of the mortars shall be removed prior to placement.
Wood racks. Wood racks used in conjunction with firework displays shall be designed and operated as follows:
- Wood racks shall be of sufficient strength to prevent adjacent mortars from being repositioned in the event that a shell detonates in a mortar, causing the mortar to burst.
- The use of wood racks shall be limited to single break shells not exceeding 6 inches (152 mm) in diameter.
- Wood racks with chain fused mortars 3 inches (76 mm) or less in diameter shall be limited to a maximum of 15 mortars per unit. Racks containing mortars 4 inches (102 mm) in diameter shall be limited to a maximum of 12 mortars. Racks containing mortars 5 inches (127 mm) to 6 inches (152 mm) in diameter shall be limited to a maximum of 10 mortars.
- Mortars placed in wood racks shall not be reloaded during the display.