8
Rigging the Installation (continued)
Rigging the Installation
Rules for Suspension
•Correct use of all suspension hardware and components is imperative in sound system rigging and deployment.
•Always calculate suspended loads before lifting to ensure suspension components and hardware are used within their respective load limits.
•Research local codes and regulations to fully understand the requirements for suspended loads in the venue in which the equipment is to be
suspended.
•Use only shackle holes for suspension of array.
•Be absolutely certain of the integrity of any structural member intended to support suspended loads. Hidden structural members can have hid-
den structural weakness.
•Consult a Professional Mechanical or Structural Engineer licensed in the jurisdiction of the sound system installation to review, verify, and
approve all attachments to the building or structure.
•Never assume anything- Owner or third-party supplied suspension attachment points may not be adequate for the loads to be suspended.
•Employ the services of a Professional Rigger for hoisting, positioning, and attaching the equipment to the supporting structure.
•Always inspect all components (enclosures, suspension brackets, pins, frames, bolts, nuts, slings, shackles, etc.) for cracks, wear, deforma-
tion, corrosion, missing, loose, or damaged parts that could reduce the strength of the assembly before lifting. Discard any worn, defective, or
suspect parts and replace them with new appropriately load-rated parts.
Shock Loading
When a load is either moved or stopped, its static weight is magnified. Sudden movements can magnify the static weight several times. This
magnification of static weight is termed "shock loading". Shock loading poses a danger to equipment and workers. The effects of shock loading
can be instantaneous, or they may remain undetected unless the equipment is visually damaged. Avoiding shock loading requires careful plan-
ning and knowledge of equipment, rigging, and lifting practices.
Shock loading of equipment and structures is usually confined to lifting and installation, but natural forces (winds, earthquakes) can impose
shock loads several times the static load. This is why structures and suspension equipment must be capable of supporting several times the
weight of the equipment suspended.
MD Working Load Limits and Design Factors
Table 1 lists the MD suspension components and provides Working Load Limit data at various Design Factors. The tabulated Design Factors are
for static loads only. The choice of which Design Factor to use will depend upon the jurisdiction and venue of installation, as well as the condi-
tions of suspension. Dynamic conditions are determined by unknown, installation-specific factors and should be referred to a Licensed Structural
Engineer for clarification before proceeding with any suspension of the equipment. The data presented is based upon the listed component
weights:
Table 1: MD Working Load Limits
Suspension Points
7:1 Design Factor
10:1 Design Factor
12:1 Design Factor
Top & Side Panels
457 lb (207 kg)
320 lb (145 kg)
267 lb (121 kg)
Rear Panels
314 lb (143 kg)
220 lb (100 kg)
183 lb (83 kg)
