Emergency Responses – Part 4 – Wall Collapse

Scenario 3 – A wall collapse

One of our premises was adjacent to a large construction site. There was a thick and high old wall separating the two plots. Over a weekend, the construction company next door excavated large volume of wet mud and stored it in the open ground on the other side of the wall. To gain maximum space, the wet mud was pushed on to the wall. Over the week-end, the wall got soaked, became soggy, could not take the load of the wet mud mass leaning on it and collapsed, bringing down a few fully grown trees with it. Parts of the wall and the tree branches penetrated the building at various points including couple of fire-proof doors, a few windows and ventilators.

A package AC out-door unit servicing the UPS room was crushed under the debris. The incident occurred on a Sunday at the stroke of midnight, during the hot summer months in Chennai. Since it happened at the stroke of midnight, there were no casualties. The security guard who had just walked past the location was the only eyewitness of the collapse and was in shock, since he had passed the area a just few seconds before the incident.

During normal working hours, there are cars parked parallel to the building and people used to come out for fresh air and used to sit underneath the trees.

The consequential problems were more pronounced than the actual structural damage to the building. The UPS room located in the basement lost its air-conditioning. Due to extreme heat, the batteries lost its charge retaining time – normally 30 minutes back up at 80% load. During one of the power outages, two gensets did not start in auto mode. By the time the gensets were started in manual mode, the UPS batteries got discharged and the data center in one of the floors was affected due to UPS power outage.

Root Cause for wall collapse.  The wall collapse was triggered by the storing wet mud on the other side. This was beyond control of the site FM team.

Root Cause for UPS Battery Failure.  Rise in room temperature had reduced the charge retention time, thus reducing the effective back up time.

Root Cause of incident leading to UPS Battery Drain.  Two of the three gensets had problems in auto starting, but were not highlighted, no log entries made, nor repair actions initiated. The duty technicians were not briefed on emergency actions on gensets and the urgency in taking them on load, to avoid UPS battery discharging – a special condition at that point of time.

 Actions taken to avoid recurrence

  • Regular monitoring of construction activities in the adjacent plots.
  • Writing down and practicing Genset emergency start operations to reduce elapsed time.
  • Educating the Duty Technicians about the importance of keeping the Log Books and other Information Boards up-to-date.
  • Educating all the duty staff on the importance of complete handing over and taking over of duties and shift briefing by the shift supervisors.
  • Educating the technical staff about the effect of high temperature on UPS and UPS Battery bank performance.

Complacency is a major threat to emergency preparedness. Regular briefing and planned mock drills with full participation of all stake holders would help in reducing the impact of emergencies.

Hope that all the readers enjoyed this series on emergencies and disaster management, covered in four parts.