This Technical Memorandum details the procedures that should generally be adopted by the Authority:
for determining (on the basis of the calculated noise level) any permitted hours of operation for percussive piling;
for the issuing of Construction Noise Permits for percussive piling pursuant to section 8 of the Ordinance; and
In this Technical Memorandum, unless the context otherwise requires, the following definitions apply:
"Authority" has the same meaning as in the Ordinance;
"Construction Noise Permit" has the same meaning as in the Ordinance;
"diesel hammer" means a device which imparts a percussive force to a pile by means of the downward motion of a ram which causes the compression and ignition of a charge of diesel fuel;
"double acting" describes the working principle of a piling hammer in which a percussive force is imparted to a pile by means of the direct or indirect impact of a ram or piston falling under the force of gravity with an additional downward force being exerted by a fluid at high pressure, the ram or piston being raised by means of a force imparted by a fluid at high pressure;
"drop hammer" means a device which imparts a percussive force to a pile by means of the direct or indirect impact of a mass falling under the force of gravity alone, the mass being raised by means of a crane or winch;
"hydraulic hammer" means a device which imparts a percussive force to a pile by means of the downward motion of a ram or piston which follows the single or double acting principle and is powered by hydraulic fluid at high pressure;
"internal drop hammer" means a drop hammer used in such a manner that the point of impact is at or near the bottom of the pile casing, the casing being a hollow steel tube within which the action of the hammer takes place;
"Ordinance" means the Noise Control Ordinance;
"percussive piling" has the same meaning as in the Ordinance;
"pile" has the same meaning as in the Ordinance;
"piling" has the same meaning as in the Ordinance;
"piling zone" means an area within which percussive piling may take place, as specified in a Construction Noise Permit;
"pneumatic or steam hammer" means a device which imparts a percussive force to a pile by means of the downward motion of a ram or piston which follows the single or double acting principle and is powered by air or steam at high pressure;
"Secretary" has the same meaning as in the Ordinance; and
"single acting" describes the working principle of a piling hammer in which a percussive force is imparted to a pile by means of the direct or indirect impact of a ram or piston falling under the force of gravity alone, the ram or piston being raised by means of a force imparted by a fluid at high pressure.