SoonerKid
October 24th, 2005, 04:41 AM
1. Size Definition
Mortar size shall be stated as the measurement of the inside diameter.
2. Materials
Mortars shall be constructed of steel, HDPE plastic, heavy gauge sheet metal, spiral, or convolute wound kraft paper tubes or fiber reinforced plastic.
All mortar material shall be of sufficient thickness and strength to withstand the forces generated by the lift charges.
Mortars larger than 12 inches in diameter shall be constructed of steel with a steel bottom plate, HDPE plastic with adequate cross bolting or equivalent, or fiber reinforced plastic with an adequately plugged bottom so as to withstand the forces produced by the lift charge.
Paper mortars shall be inspected before each use to insure they have not been weakened by loose and unwinding layers.
Sheet metal mortars shall be limited to 3 inch diameter or smaller and shall be used for single shot, single break shells in finales or barrages only. The seam shall be placed at 90 degrees to the right or left of the Operator.
3. Plugs
All mortars shall be securely plugged at the bottom. Solid wood may be used.
For mortars up to 6 inches in diameter, the thickness of the plug shall be at least equal to ½ the inside diameter of the mortar.
Paper mortars shall have a plug thickness equal to or greater than the inside diameter of the mortar.
All plugs shall fit tightly against the inside of the mortar.
Plugs shall be secured with at least 4 screws, nails, or staples set 90 degrees apart and penetrating at least ½ the diameter of the plug. Alternatively, two bolts may be used which are installed in a 90 degree cross pattern, provided they are at least 5/16ths of an inch in diameter and are secured with the head and the nut/lock washer on the outside of the tube. Mortars greater than 6 inches in diameter shall have more fasteners.
Steel mortars shall have a steel plate welded in/on the bottom, provided the weld is of good quality and forms a continuous water tight seal. The plate shall be equal to or greater than the wall thickness of the mortar. It is recommended that large caliber mortars or mortars for firing large multi-break shells have substantial bottom plates installed. The Safety Team shall inspect such mortars as to their integrity.
HDPE plastic mortars up to and including 4 inches in diameter may be of a one-piece style with a molded bottom.
4. Length
Mortars up to 6 inches in diameter shall have an inside length (excluding the plug) of at least five times their inside diameter.
Mortars above 6 inches in diameter shall have a sufficient length to propel the type of shells fired to the proper height.
Mortars used to fire long or multi-break shells shall be of sufficient length to propel the shell to the proper height.
5. Defects
Mortars with cracks, splits, bulges, excessive corrosion, loose or split plugs, delaminated paper tubes, or gaps between the plug and inside wall shall not be used.
Mortars with dents, bends, or restrictions along their length or at the muzzle shall not be used.
6. Burial
Mortars not in racks shall have a minimum of ¾ of their length buried in the ground. All mortars to be used above ground shall be constructed of HDPE plastic, paper, or fiber reinforced plastic. Single mortars may be secured in sand boxes or troughs and shall have a minimum of ½ their length covered with rock and gravel free sand. A drum may be used only if it is constructed of HDPE plastic and it contains only one mortar of 12 inch maximum inside diameter and it has been inspected by the Safety Team for possible tip-over. Under no circumstances will free standing or staked and tied mortars be allowed. Mortar separation shall be a minimum of ½ the diameter of the larger mortar and shall be placed a minimum of ½ the mortar diameter from the box, drum, or trough walls.
7. Racks
Racks for holding mortars shall hold the mortars securely and be constructed to stand up to the required forces. The maximum size mortars to be used in racks shall be 6 inch inside diameter.
Mortar racks shall be adequately braced to prevent tip-over and shall be placed perpendicular to the spectators.
8. Protection
All loaded mortars shall be sealed with taped down foil, cap plugs, or other equivalent means of protection when the following conditions occur:
Mortars will be left overnight.
Other display material could drop sparks into the mortars causing pre-ignition.
Rain or other precipitation is forecast or present.
Paper mortars shall be protected from excessive moisture, and if buried in sand or earth, they shall be wrapped in plastic.
Mortar size shall be stated as the measurement of the inside diameter.
2. Materials
Mortars shall be constructed of steel, HDPE plastic, heavy gauge sheet metal, spiral, or convolute wound kraft paper tubes or fiber reinforced plastic.
All mortar material shall be of sufficient thickness and strength to withstand the forces generated by the lift charges.
Mortars larger than 12 inches in diameter shall be constructed of steel with a steel bottom plate, HDPE plastic with adequate cross bolting or equivalent, or fiber reinforced plastic with an adequately plugged bottom so as to withstand the forces produced by the lift charge.
Paper mortars shall be inspected before each use to insure they have not been weakened by loose and unwinding layers.
Sheet metal mortars shall be limited to 3 inch diameter or smaller and shall be used for single shot, single break shells in finales or barrages only. The seam shall be placed at 90 degrees to the right or left of the Operator.
3. Plugs
All mortars shall be securely plugged at the bottom. Solid wood may be used.
For mortars up to 6 inches in diameter, the thickness of the plug shall be at least equal to ½ the inside diameter of the mortar.
Paper mortars shall have a plug thickness equal to or greater than the inside diameter of the mortar.
All plugs shall fit tightly against the inside of the mortar.
Plugs shall be secured with at least 4 screws, nails, or staples set 90 degrees apart and penetrating at least ½ the diameter of the plug. Alternatively, two bolts may be used which are installed in a 90 degree cross pattern, provided they are at least 5/16ths of an inch in diameter and are secured with the head and the nut/lock washer on the outside of the tube. Mortars greater than 6 inches in diameter shall have more fasteners.
Steel mortars shall have a steel plate welded in/on the bottom, provided the weld is of good quality and forms a continuous water tight seal. The plate shall be equal to or greater than the wall thickness of the mortar. It is recommended that large caliber mortars or mortars for firing large multi-break shells have substantial bottom plates installed. The Safety Team shall inspect such mortars as to their integrity.
HDPE plastic mortars up to and including 4 inches in diameter may be of a one-piece style with a molded bottom.
4. Length
Mortars up to 6 inches in diameter shall have an inside length (excluding the plug) of at least five times their inside diameter.
Mortars above 6 inches in diameter shall have a sufficient length to propel the type of shells fired to the proper height.
Mortars used to fire long or multi-break shells shall be of sufficient length to propel the shell to the proper height.
5. Defects
Mortars with cracks, splits, bulges, excessive corrosion, loose or split plugs, delaminated paper tubes, or gaps between the plug and inside wall shall not be used.
Mortars with dents, bends, or restrictions along their length or at the muzzle shall not be used.
6. Burial
Mortars not in racks shall have a minimum of ¾ of their length buried in the ground. All mortars to be used above ground shall be constructed of HDPE plastic, paper, or fiber reinforced plastic. Single mortars may be secured in sand boxes or troughs and shall have a minimum of ½ their length covered with rock and gravel free sand. A drum may be used only if it is constructed of HDPE plastic and it contains only one mortar of 12 inch maximum inside diameter and it has been inspected by the Safety Team for possible tip-over. Under no circumstances will free standing or staked and tied mortars be allowed. Mortar separation shall be a minimum of ½ the diameter of the larger mortar and shall be placed a minimum of ½ the mortar diameter from the box, drum, or trough walls.
7. Racks
Racks for holding mortars shall hold the mortars securely and be constructed to stand up to the required forces. The maximum size mortars to be used in racks shall be 6 inch inside diameter.
Mortar racks shall be adequately braced to prevent tip-over and shall be placed perpendicular to the spectators.
8. Protection
All loaded mortars shall be sealed with taped down foil, cap plugs, or other equivalent means of protection when the following conditions occur:
Mortars will be left overnight.
Other display material could drop sparks into the mortars causing pre-ignition.
Rain or other precipitation is forecast or present.
Paper mortars shall be protected from excessive moisture, and if buried in sand or earth, they shall be wrapped in plastic.