ADMINISTRATIVE REPORT

Date: September 22, 1998

Author/Local:Tom Timm/7522

RTS No: 00088

CC File No: 3759

TO:	Vancouver City Council
FROM:	City Building Inspector
SUBJECT:	Alder Bay Housing Co-Op, Explosion

RECOMMENDATION

A)THAT the City Building Inspector be authorized to retain a consultant/s to provide advice with regard to any hazard to buildings associated with soil gas emissions in the south False Creek area.

B)THAT $30,000 be provided from contingency reserve as an interim budget for this work and that staff report back for approval of additional funding if the consultant’s estimate for this work exceeds this budget.

GENERAL MANAGERS COMMENTS

The General Manager of Community Services RECOMMENDS approval of A and B.

COUNCIL POLICY

Department Heads who are members of the Corporate Management Team may approve the appointment of consultants where the gross cost does not exceed $30,000.

PURPOSE

This report is to update Council on what is known about the explosion at the Alder Bay Housing Co-Op on Monday, September 14, 1998, to describe the various investigations that are ongoing, and to recommend that a consultant be retained to advise the City Building Inspector with regard to any longer term risks associated with the low levels of methane gas that have been detected and on mitigation measures which may be needed.

BACKGROUND

At about noon on Monday, September 14, 1998, there was an explosion in the transformer vault in the basement of one of the buildings of the Alder Bay Housing Co-op and in the underground duct containing the main BC Hydro connection to the vault. The Co-Op is located in the residential development area along the south shore of False Creek to the east of the Granville Bridge. The explosion did some damage in the basement of the building. The doors to the transformer vault, the outer doors to the electrical meter room and an exterior door leading from the corridor outside of the electrical room were blown out by the force of the explosion. Ventilation ducts in the area were also damaged as was a frame wall between the corridor and a laundry room. A maintenance worker who was just about to open the exterior door to enter the basement was hit by the door as it blew open and was thrown back by the force of the blast. He sustained minor injuries. A woman who was in the laundry room at the time was apparently uninjured.

At about 10:00 PM that night it was determined that the building was safe to re-occupy on condition that arrangements were made for continuous gas monitoring through the night and for a continuous fire watch/security patrol because the building fire alarm system was out of service. The residents spent the night without electricity. Power was eventually restored at about 1:00 A.M. on Wednesday morning.

Fire investigators initially concluded that there was some kind of a gas explosion of unknown origin. There is no natural gas service to this building or the surrounding area. The explosion appears to have been centred in a pit in the floor of the transformer vault through which the main electrical service enters the vault, in an underground vault, or "pull box" about 100 feet away along the Hydro duct, and in the Hydro manhole on Lamey’s Mill Road.

DISCUSSION

Several investigations have begun to determine the cause of this explosion and to ensure that something similar does not happen again:

-The day after the event the City Building Inspector ordered the Co-Op to carry out a study to determine the cause of the explosion and to ensure that there is no risk of are-occurrence. This order was based on Section 1.10.16 of the Building By-Law which states that;

"The authority having jurisdiction may issue to the owner an order in writing as set out in section 1.14 to correct any unsafe condition observed in any building."

-The land along the south shore of False Creek is City owned and leased on a long term basis to the various housing co-ops and Strata Councils that own the buildings. The City, as the land owner also has an interest in determining the cause of this explosion. Through the Real Estate Division the City has retained a consultant to investigate on behalf of that interest.

-B C Hydro is investigating what role their facilities may have had in this event. There was a power outage in this area on the morning of the explosion and BC Hydro is investigating the possibility that electrical arcing on one of their cables when the power was turned back on, may have provided the source of ignition. It has also been suggested that an explosive gas other than methane may have been present in the Hydro duct, possibly as a result of deterioration of the cable insulation. Hydro is also investigating this possibility.

-City staff from the Environmental Protection Branch have begun a program of atmospheric testing in all poorly ventilated spaces in buildings throughout the residential area of south False Creek. To date, after testing approximately 30 buildings, low levels of explosive gasses, in the range of 1% to 6% of the lower explosive limit (LEL) have been detected in approximately six locations. The LEL is the level at which WCB regulations require a confined space to be ventilated before any worker enters the space.

The investigation that the Alder Bay Housing Co-Op is undertaking is specific to their buildings. The investigation that the Real Estate Division has undertaken is specific to the City’s interest as the owner of the land. Separate from the City’s interest as the land owner, the City Building Inspector has the obligation to administer the Vancouver Building By-law. This includes the authority to order any unsafe condition in a Building to be corrected.

The investigations to date have uncovered some low levels of methane which do not represent an immediate risk of explosion. However, given the fact that an explosion did occur, and that methane or soil gas may have been the cause, there may be a concern that an unsafe condition could develop in the longer term.

There is a need for a separate, independent evaluation of the risk, if any, to buildings in the area related to the low levels of methane gas that have been detected in several buildings throughout the area. This evaluation is necessary in order for the City Building Inspector to assess whether or not any remedial measures should be ordered for any buildings in the area.

We do not have the technical expertise in house to carry out this work. Therefore this report recommends that a consultant be retained to advise the City Building Inspector on this issue. The terms of reference for this study would require the consultant to:

1.Advise on the adequacy of the testing program carried out by City staff to evaluate the potential for hazardous accumulations of gas, and to recommend what additional testing or monitoring should be carried out.

2.Carry out any recommended testing program and to report on the results. This will be subject to review and approval of these recommendations by the City Building Inspector.

3.Review research papers on this subject and similar cases in other Cities and to prepare a summary report on the measures taken in other jurisdictions.

4.Report on the risks, if any, associated with the levels of gas found to be present and to recommend the range of measures that may be possible or necessary to mitigate that risk.

5.Identify any relevant standards for acceptable concentrations of methane in buildings which could be applied in Vancouver.

FUNDING AND COST

Staff do not have an estimate of the cost of this consulting assignment. In order to expedite the work it is proposed that an interim budget of $30,000 be approved, and that staff report back to Council for approval of additional funding if the consultant’s estimate exceeds this amount. The consultant would be allowed to start work prior to approval of this additional funding on the understanding that the contract will be terminated, or curtailed if additional funding is not approved.

* * * * *

(c) 1998 City of Vancouver