Engineering: June 2009 Archives

In Excavation and Trenching Safety, safety engineering expert James Umack, writes:

Competent Person

The competent person has the responsibility to examine the area of the excavation to determine that no recognizable conditions exist which would expose employees to injury from possible moving ground before work is permitted in or adjacent to the excavation. The excavation must not be opened until the competent person has determined that it is safe to do so. The competent person must inspect the excavation at the beginning of each day before workers are exposed to ensure that no changed condition, such as water entering the excavation, has increased the danger. Excavations must be inspected by the competent person after every rainstorm or other hazard-increasing occurrence and the protection against slides and cave-ins increased, if necessary, before excavation activities resume.

Below Grade Hazards

Before opening the excavation, the location of all underground installations such as sewer, water, fuel, electric lines, telecommunication lines, tanks, etc., must be located and marked so that they may be avoided or approached with caution. Many regions have a single telephone number that will alert the owners or managers of underground installations that an excavation is intended that may impact their facility or equipment. The operator of that underground installation then is required to mark on the ground their approximate location.

 

In Excavation and Trenching Safety, safety engineering expert James Umack, writes:

Excavation and trenching may present substantial risk of injury to person working in the excavation or adjacent to the edge. Safety guidelines have been developed through years of experience working with and in excavation. Many of these guidelines have been adopted by OSHA and have been made mandatory for all trenching and excavating activities.

Permits

Many jurisdictions require a permit before commencing large excavation activities to ensure the safety not only of the workers but also of the community. The permit notifies the regulatory agency of the excavation activity and requires the organization doing the digging to place a competent and knowledgeable person in charge of the dig. The permit may be specific for a single excavation or may be issued on an annual basis for a firm that does many excavations.

Engineering expert Dr. Dennis Torok has been invited to provide opinions on the possible causes of the significant increase in home runs being hit in the "new" Yankee Stadium.  Torok is an expert in wind effects around buildings and stadiums and says there are several ways to reduce the wind patterns at Yankee Stadium without altering the playing field. The team could change the slope of the roof or put attachments on it to deflect wind that whips into the stadium.  Marketwire reports:

Structural design and directional orientation of baseball stadiums can affect wind patterns and spatial distribution of wind speeds within the confines of a stadium both at ground level and higher elevations. This can influence the flight trajectories and distance traveled by baseballs. Wind approaching from certain directions can exacerbate the effects. The study of stadium-related wind effects, early in the design phase of proposed stadiums and prior to structural renovations on existing stadiums, can yield further understanding as to a stadium's potential labeling as a "hitter-friendly" or "pitcher-friendly" ballpark.