Gage-Babcock & Associates Safety Assessment ... - District of Sechelt

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GAGE-BABCOCK & ASSOCIATES LTD.
228 1125 1’, SHOAD\IAY. VANCOUVIAI, BC CANADA V6H X5 • TEL ELL.732-3/51 • FAX 504-127 277 • ;jvj’’ obcri.com
mezzanines, galleries and raised walkways, shall be protected by a guard
walking surface and the adjacent surface, or
a) there is a difference in elevation of more than 600 nun between the
is provided for other than maintenance purposes, including but not limited
on each side that is not protected by a wall for the length where
to flights of steps and ramps, exterior landings. porches, balconies,
1) Except as provided in Sentences (2) and (3), every surface to which access
(See Appendix A.) iSee also Article 97.5.3.)
9.8.8.1. Required Guards
difference in adjacent levels is more than 600 mm. Of specific interest to this case, are the
provisions of Division B - Sentence 9.8.8.1.(l), which states:
2. The BCBC provides requirements for guards or other protection at locations where the
3.7 m, and the grades may have slopes of up to 350(1 in 1.4).
rock retaining walls and sloped grades. The retaining walls have a maximum height of about
steeply sloping site. Lot grading suitable for building is achieved with a series of stacked
1. The Seawatch project is a single-family subdivision comprised of 28 building lots set on a
Sechelt project on July 23, 2012 to review various stacked rock retaining walls and sloped grades
for compliance with the safety requirements contained in the 2006 British Columbia Building Code
(BCBC) and its referenced standards. Specifically, the review focused on the requirements for
guards or other physical barners adjacent to steep slopes or retaining walls with significant drops.
This letter describes our findings.
Gage-Babcock & Associates Ltd. (GBA) attended the Concordia Homes - Seawatch Subdivision,
Code Assessment of Stacked Rock Retaining Walls and Slopes
RE: Concordia Homes - Seawatch Subdivision, Sechelt GBA File # 121870
Dear Mr. Tang:
Attn: Ken Tang, P.Eng. Via e-mail: KTang@sechelt.ca
P0 Box 129
5797 Cowrie Street, 2T Floor
District of Sechelt
Sechelt, BC VON 3A0
August21, 2012
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A-9.8.8.1. Required Guards. The requirements relating to guards stated in Part
slope of more than 1 in 2.
b) the adjacent surface within 1.2 m of the walking surfice has a
GBA# 121870 August21, 2012
EFA
any building. The Code (letines an unsafr condition as “any condition that could cause
undue hazard to life, limb or health oF any person authorized or expected to be on or about
the premises.”
of Division A states that the Code applies to the colTection ofan unsa/’ condition in or about
3. In addition to the specific requirements o.fJ3CBC Sentence 9.8.8.1 .( 1), Clause 1.1.1.1 .(l)(h)
Required Iocotion5 of guards
FiqureA H3.I3.J.
and consequently where guards would be required include, but are not limited to,
not parallel to the walking surface or the surface of the treads or ramps.
in exterior settings, surfaces adjacent to walking surfaces, stairs or ramps often are
A-9.8.8.5.(l) and (2), A-9.8.8.5.(3) and A-9.8.8.6.
sufficiently strong that a person cannot Call through it. Where there is no wall, a
additional requirements apply to guards to ensure that a minimum level of
protection is provided. These relate to the characteristics described in A-9.8.8.3.,
the higher surface will obviously prevent such a fall, provided the wall is
some kind of barrier to reduce the chances of such a fall. A wall along the edge of
Examples of such surfaces where the difference in elevation could exceed 600 mm
Consequently, the walking surface, stair or ramp may need protection in some
guard must be installed. Because guards clearly provide less protection than walls,
landings, porches, balconies, mezzanines, galleries, and raised walkways. Especially
guards. This provides little or no protection for the users. That is why the
locations but not in others. (See Figure A-9.8.8.1.) Iii some instances, grades are
artificially raised close to walking surfaces, stairs or ramps to avoid installing
requirements specifr differences in elevation not only immediately adjacent to the
construction but also for a distance of 1 200 mm from it by requiring that the slope
of injury in a fall from the higher surface is sufficient to warrant the installation of
of the ground be within certain limits. (See Figure A-9.8.8.1.)
is provided for other than maintenance purposes and the next lower surface, the risk
mm or more between two floors, or between a floor or other surface to which access
9 are based on the premise that, wherever there is a difference in elevation of 600
Concordia Homes Subdivision, Sechelt, BC
Code Assessment on the Stacked Rock Retaining Walls and Slopes Page 2

Code Assessment on the Stacked Rock Retaining Walls and Slopes Page 3
Concordia Homes Subdivision, Sechelt, BC
GBA# 121870 August21, 2012
4. The provisions ofDivision B - Sentence 9.8.8.l.(1), in conjunction with Division A - Clause
1. 1.1. 1.(1)(h) clearly require guards or similar forms of protection where exterior walking
surfaces are located within 1200 mm of steep slopes or elevation differences of more than
600 mm between the adjacent surfaces. Sidewalks and patios are considered to be exterior
walking surfaces within the context of the Code.
Other walkable surfaces, such as lawns, would appear to be outside of the context of
Sentence 9.8.8.1 .( 1), but could be considered to be within the context of an unsafe condition
if the lawn is located immediately adjacent to a retaining wall or steep slope.
Recommendations
1. In general, exterior walking surfaces such as sidewalks, patios, driveways and similar hard
surfaces are located at least 1.2 m away from the stacked rock retaining walls and steep
slopes, and do not require guards under the provisions of BCBC Sentence 3.8.8.1.(1).
2. At Units 23 and 24, the grade level patios at the rear of the houses are located sufficiently
close to retaining walls to constitute a hazard, and require guards or other protection under
the provisions of Sentence 9.8.8.1.(1).
3. Lawns and similar spaces that are likely to be occupied on a regular basis should be provided
with guards, or other suitable barriers, where required to prevent an unsafe condition at
retaining walls and steep slopes.
4. Where landscaping or shrubbery is used to provide a safety barrier adjacent to retaining walls
and steep slopes, the plantings should be dense enough to prevent inadvertent access to
within 1.2 m of the edge of the wall or slope.
Sincerely,
GAGE-BABCOCK & ASSOCIATES LTD.
Bruce Campbell
Senior Consultant
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