Workers entering sumps may encounter an oxygen-deficient atmosphere. Also, because of the wet nature of the sump, electrical shock hazards are present when power tools are used inside. Sumps are often poorly illuminated. Inadequate lighting may create an accident situation. These large below-grade areas are characterized by little or no air movement.
Ventilation is always a problem.
In addition, the possibility of oxygen deficiency exists. As well, welding and other gases may easily collect in these areas, creating toxic atmospheres. As these structures near completion, more confined spaces will exist as rooms are built off the existing structure. Electrical Transformers Electrical transformers are located on the jobsite. They often contain a nitrogen purge or dry air.