Significant Potential Incident

Significant Potential Incident

Unauthorized Weld on Pressurized Water LineUnauthorized Weld on Pressurized Water Line

Timmins, Ontario, CanadaTimmins, Ontario, Canada

October 17, 2011October 17, 2011

SERIOUS INCIDENT REVIEWSERIOUS INCIDENT REVIEW

• Equipment: Steam Generator 1

• Time/Date: Reported date October 17, 2011

• Location: Timmins, Micronizing Plant

• Conditions: Normal Running Conditions

• Workgroup: Maintenance

• Supervisor: Ray Drouin

• Manager: Yahia (John) Aoumer

Scenario description

A boiler feed water leak was discovered on the 2” feed water piping between steam generator 1 thermizer and super heater 1.The employee informed the Process Technologist who was supervising another job in the boiler room.

While discussing the repair options for the leak it was pointed out by the Millwright employee that a larger section of pipe should be replaced. He identified where a previous patch weld repair was performed.

The employee then showed the Process Technologist the location of the weld repair. The patch weld repair was located on the side of the 2” boiler feed water line. This line routinely experiences temperatures in the 250 ˚F range and pressures in the operating range of 400 to 600 psi.

Risk Score= Consequence × Likelihood

Consequence Descriptors

Likelihood Descriptors

Likelihood Likelihood description Frequency Substance Exposure

ALMOST

CERTAIN

Recurring event during the life-

time of an operation /

project

Occurs more than twice per

year

Frequent (daily) exposure at >

10 x OEL

LIKELY

Event that may occur

frequently during the life-

time of an operation /

project

Typically occurs once or twice

per year

Frequent (daily) exposure at >

OEL

POSSIBLEEvent that may occur during

the life-time of an operation

/ project

Typically occurs in 1-10 years

Frequent (daily) exposure at >

50% of OEL

Infrequent exposure at > OEL

UNLIKELYEvent that is unlikely to occur

during the life-time of an

operation / project

Typically occurs in 10-100

years

Frequent (daily) exposure at >

10% of OEL

Infrequent exposure at > 50%

of OEL

RARE

Event that is very unlikely to

occur very during the life-

time of an operation /

project

Greater than 100 year event

Frequent (daily) exposure at <

10% of OEL

Infrequent exposure at > 10%

of OEL

What Happened

• Maintenance Leader found a small leak from a pressurized water line in the boiler room

• Maintenance Leader took it upon himself to patch weld the leak

• Maintenance Leader did not inform the Plant Supervisor of his actions.

Immediate Response

• When Management becomes aware of the weld, the whole pipe is replaced immediately

• Incident rated as a Significant Potential Incident

• Taproot investigation begins.

Photos of the incident site and scene

Weld on pipeWeld on pipe

pipe removed and in the recycle bin in this picture

Winter Snap ChartWinter Snap Chart

Mitigating FactorsMitigating Factors

• Employee eventually reported the welding job 9 weeks later to a Member of Management.

Contributing / Causal Factors

• No Preventive Maintenance exists for inspections on water/steam lines

• No Supervisory Personnel notified of leak

• Welding event does not get reported to Management

• Employee decides to perform repairs to water line

Root Cause & Corrective Actions

Root Cause & Corrective Actions

Root Cause & Corrective ActionsRoot Cause & Corrective Actions

Root Cause & Corrective ActionsRoot Cause & Corrective Actions

Root Cause & Corrective Actions

Root Cause & Corrective Actions

Root Cause & Corrective Actions