08 - Sensitivity of Equipment and Stock

Plant, equipment, machinery, storage racks, etc. are critical for business operations. Damage to such components, resulting in business interruption, has been reported in earthquakes with intensities as low as MMI VII (Modified Mercalli Intensity). Since the contents of the building, in terms of equipment and machinery, are usually not defined at the time the building is designed, these elements are usually not designed for earthquake forces.

In addition, equipment and machinery are “off-the-shelf” elements, which are not designed for the unique local conditions. Structural design codes in seismic regions define the design and detailing requirements for non-structural elements and their foundations.

Hazards

  • Tall equipment are particularly susceptible to overturning due to their high center of gravity.
  • Piping connected to the equipment are potential weak points, which can be damaged during shifting of equipment.
  • Missing anchorage bolts connecting the equipment to the foundations.
  • Rotating machinery are sometimes provided with vibration isolation, which are designed for vertical dynamic but not lateral forces.
  • Unreinforced masonry or concrete block walls are a common feature of industrial buildings. Collapse of these, which can occur even at low seismic force levels, are a hazard not only to the equipment but also to worker safety.
  • Poor anchorage of tanks and equipment piping. Tall equipment or liquid containers are especially susceptible to damage if not properly anchored. Piping connected to such equipment, if not provided with flexible joints and suitable bracing, are also susceptible to damage.

Controls

  • Any piping connected to the equipment should also take seismic deformations into account, eg. provide flexible joints, avoid connection to unreinforced masonry or concrete block walls, brace the pipes against swaying.
  • Follow best practice guidelines or, if available, national seismic design requirements for steel storage racks. These can collapse and result in loss of stored material as well as injury to staff. Publically-available documents exist, eg. FEMA 460) describing maintenance of such elements in seismic regions.
  • Machinery and equipment are to be anchored with structural anchors to the foundations. The configuration and types of anchors as well as foundation capacity are all to be checked by a qualified structural engineer. This issue is especially critical for tall equipment and rotating machinery. Confirm with the equipment supplier that the anchorage conforms to local seismic force levels, as defined in the national structural design code.
  • Ensure that roof-mounted equipment have been considered in the seismic analysis during building design. If such equipment is subsequently added to the building, the potential influence on the structure’s dynamic characteristics should be controlled by a qualified structural engineer.

Assess plant and equipment volatility to earthquake related damage, and provide adequate anchoring and bracing according to local standards and international codes.