CSA Z800:2018 pdf download.Guideline on basement flood protection and risk reduction
1.1 General
This Guideline covers measures to reduce the risks of basement flooding, and to mitigate the adverse effects on property, public safety, and public health in case of a flood event. It covers existing, new,rebuilt, and renovated houses in rural and urban settings.
1.2 Buildings covered
This Guideline covers all types of ground-related houses, with or without basements, that are considered Part 9 buildings according to the National Building Code (NBC) including
a) detached houses;
b) semi-detached houses; and
c) row houses.
Recommendations made in this Guideline are generally appropriate for houses serviced by gravity-based storm, sanitary, combined, or third pipe systems.
1.3 Types of flood hazards
The types of flood hazards addressed by the measures described in this Guideline are
a) overland flooding associated with precipitation events and resulting in the accumulation/ ponding of rainwater and/or snow melt in and around ground-related houses;
b) storm and sanitary sewer backwater (surcharge);
c) infiltration flooding (groundwater seepage);
d) plumbing and drainage failures, including failure of sump systems and sewer lateral failure; and
e) flooding associated with improper installation of basement flood risk-reduction technologies (see Annex A).
Note: Users of this Guideline are reminded that any of the provisions outlined herein are subject to existing codes and standards that are applicable in the jurisdiction under which the Guideline user is operating. It is strongly recommended that appropriate licensed professionals conduct any work outlined in this Guideline. All appropriate local, provincial, and national codes and standards must be adhered to in the application of the provisions outlined herein. All appropriate permits and inspections from authorities having jurisdiction must be obtained when undertaking any of the work outlined here.
4.2 Overland flooding
Overland flooding includes flooding associated with precipitation events and the resulting accumulation/ponding of rainwater and/or snowmelt in and around houses. In the example presented in Figure 1, stormwater flows have exceeded the capacity of stormwater conveyance systems. Water is flowing toward the home via the surface of the lot and entering through above-grade openings,including windows and doors.
Types of overland flooding that are addressed in this Guideline include
a) overland flooding associated with stormwater flows (e.g, resulting from undefined major drainage systems or flows exceeding major drainage system capacities);
b) overland flooding associated with ponding or accumulation of rainwater near foundation walls as a result of poor lot grading and drainage, or extreme rainfall events that exceed the capacity of the drainage design; and
overland flooding associated with storm or sanitary backup that has surcharged above ground.
Note: All drainage systems are different, and it can be difficult to diagnose the cause of flooding in any instance. As outlined in this Guideline, detailed plumbing investigations will likely be required to provide a comprehensive understanding of flood causes for any individual house.
Residential structures are unable to withstand the forces associated with even minor floodwater depths, unless specifically designed to do so. Thus, the basement flood-protection measures presented in this Guideline focus on keeping stormwater, groundwater/seepage, and sewer-backup-related floodwaters away from structures, rather than designing structures themselves to become watertight.CSA Z800 pdf download.