Preliminary Results From Field Experimental Study Of Rain...

Preliminary Results From Field Experimental Study Of Rain Load And Penetration Into Wood-frame Wall Systems At Window Sill Defects

E. Ngudjiharto1, F. Tariku2, and P. Fazio1 1Building, Civil and Environmental Engineering, Concordia University, Montréal, Canada. 2Building Science Centre of Excellence, British Columbia Institute of Technology, Burnaby, Canada

Current State of WDR Research

 Research in predicting the quantity of WDR impacting walls.

 Guides on estimating the hygrothermal performance of wall assemblies are abundant.

× Still missing: the correlation between the rain penetration and the WDR.

Buildings for Tomorrow Conference – Toronto Canada - October 28-30, 2014

14th Canadian Conference on Building Science and Technology 2

Current State of WDR Research

•  “In the absence of specific full-scale test methods and data for the as-built exterior wall system being considered, the default value for water penetration through the exterior surface shall be 1% of the water reaching the exterior surface.” (ANSI/ASHRAE Standard 160, 2009)

Buildings for Tomorrow Conference – Toronto Canada - October 28-30, 2014

14th Canadian Conference on Building Science and Technology 3

Today’s Presentation: Field Experimental Study •  Introduction

• Methodology

• Preliminary Results

•  Findings So Far

• What’s Next?

Buildings for Tomorrow Conference – Toronto Canada - October 28-30, 2014

14th Canadian Conference on Building Science and Technology 4

Introduction

• OBJECTIVE: To find the correlations between measured amount of rainwater collected through various specified defects to the corresponding rain and wind data recorded during fall and winter rain events in BC.

•  This paper presents the preliminary findings from one defect type at one of the stucco wall panels during the month of September 2013.

Buildings for Tomorrow Conference – Toronto Canada - October 28-30, 2014

14th Canadian Conference on Building Science and Technology 5

Research Variables

• WDR parameters (horizontal rain, the wind speed & direction) and rain duration.

• Wall cladding types (stucco and vinyl siding).

• Wall defect types at window sill.

Buildings for Tomorrow Conference – Toronto Canada - October 28-30, 2014

14th Canadian Conference on Building Science and Technology 6

Test Facility

Google Street View

Buildings for Tomorrow Conference – Toronto Canada - October 28-30, 2014

14th Canadian Conference on Building Science and Technology 7

Test Facility

Google Street View

Buildings for Tomorrow Conference – Toronto Canada - October 28-30, 2014

14th Canadian Conference on Building Science and Technology 8

Monitoring Types

•  Leakage rate monitoring.

•  Long-term hygrothermal monitoring (temperature & moisture content at wood studs, plates & sheathing, and relative humidity in wall cavity).

• WDR, outdoor & indoor conditions.

Buildings for Tomorrow Conference – Toronto Canada - October 28-30, 2014

14th Canadian Conference on Building Science and Technology 9

South East façade

Buildings for Tomorrow Conference – Toronto Canada - October 28-30, 2014

14th Canadian Conference on Building Science and Technology 10

Wall construction

Buildings for Tomorrow Conference – Toronto Canada - October 28-30, 2014

14th Canadian Conference on Building Science and Technology 11

Wall installation

Buildings for Tomorrow Conference – Toronto Canada - October 28-30, 2014

14th Canadian Conference on Building Science and Technology 12

Wall installation

Buildings for Tomorrow Conference – Toronto Canada - October 28-30, 2014

14th Canadian Conference on Building Science and Technology 13

Stucco cladding

14th Canadian Conference on Building Science and Technology

Buildings for Tomorrow Conference – Toronto Canada - October 28-30, 2014

14

Finished walls

Buildings for Tomorrow Conference – Toronto Canada - October 28-30, 2014

14th Canadian Conference on Building Science and Technology 15

Instrumentation

•  WDR parameters (horizontal rain, the wind speed & direction) and rain duration.

•  Wall cladding types (stucco and vinyl siding).

•  Wall defect types at window sill.

Buildings for Tomorrow Conference – Toronto Canada - October 28-30, 2014

14th Canadian Conference on Building Science and Technology 16

Instrumentation

Buildings for Tomorrow Conference – Toronto Canada - October 28-30, 2014

14th Canadian Conference on Building Science and Technology 17

Stucco Wall 6

Buildings for Tomorrow Conference – Toronto Canada - October 28-30, 2014

14th Canadian Conference on Building Science and Technology 18

Stucco wall 6

Buildings for Tomorrow Conference – Toronto Canada - October 28-30, 2014

14th Canadian Conference on Building Science and Technology 19

Leakage tipping bucket gauge

Buildings for Tomorrow Conference – Toronto Canada - October 28-30, 2014

14th Canadian Conference on Building Science and Technology 20

Preliminary Results

Buildings for Tomorrow Conference – Toronto Canada - October 28-30, 2014

14th Canadian Conference on Building Science and Technology 21

Preliminary Results

Buildings for Tomorrow Conference – Toronto Canada - October 28-30, 2014

14th Canadian Conference on Building Science and Technology 22

Preliminary Results

• Wind-driven rain (WDR) onto south east façade of test facility:

Buildings for Tomorrow Conference – Toronto Canada - October 28-30, 2014

14th Canadian Conference on Building Science and Technology 23

WDR Calculation

• Rwdr = DRF(rh) • cos (θ) • V(h) • rh

(Blocken and Carmeliet 2010; Straube and Burnett 2000)

• DRF(rh) = driving rain factor which depends on the terminal velocity of raindrops: •  DRF (rh) = 1/ Vt (d)

•  Vt (d) = -0.166033 + 4.91844d – 0.888016d2 + 0.054888d3

•  D-50 = 1.30 rh0.232

* 0.69 1/n

(Best 1950)

14th Canadian Conference on Building Science and Technology

Buildings for Tomorrow Conference – Toronto Canada - October 28-30, 2014

24

Preliminary Results

• Calculated hourly WDR intensity plotted against measured hourly rain intensity on SE façade near W6 by Top North gauge:

Buildings for Tomorrow Conference – Toronto Canada - October 28-30, 2014

14th Canadian Conference on Building Science and Technology 25

Preliminary Results

• Calculated hourly WDR intensity plotted against measured hourly rain intensity on SE façade near W6 by Bottom North gauge:

Buildings for Tomorrow Conference – Toronto Canada - October 28-30, 2014

14th Canadian Conference on Building Science and Technology 26

Comparison  of  the  occurrence  and  intensity  of  the  calculated  wind-­‐driven  rain  on  SE  façade  to  the  measured  leakage  amount  through  corner  defect  of  W6  by  leakage  gauge:  

Buildings for Tomorrow Conference – Toronto Canada - October 28-30, 2014

14th Canadian Conference on Building Science and Technology 27

Findings So Far

•  There are good correlations between the measured and calculated wind-driven rain on the walls.

•  There are some correlations between the wind-driven rain parameters (horizontal rain, the wind speed & direction, and rain duration) and rain penetration for the specific wall defect type.

• Results indicate correlations to be explored further for better predictions of rain penetration through wall defects.

Buildings for Tomorrow Conference – Toronto Canada - October 28-30, 2014

14th Canadian Conference on Building Science and Technology 28

What’s Next?

• Analyze WDR and leakage data collected for the vinyl siding walls.

• Compare the effects of the different cladding materials (vinyl siding and stucco) on rain penetration.

• Compare the effects of the different wall defect types on rain penetration.

• Compare the hygrothermal performance of the walls of different cladding and defect types.

Buildings for Tomorrow Conference – Toronto Canada - October 28-30, 2014

14th Canadian Conference on Building Science and Technology 29

Bibliography •  ANSI/ASHRAE Standard 160. 2009. Criteria for moisture-control design analysis in buildings. American

Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc., Atlanta, GA. •  Best, A.C. 1950. The size distribution of raindrops. Quarterly Journal of the Royal Meteorogical Society, 76:

16-36. •  Blocken, B., and Carmeliet, J. 2010. Overview of three state-of-the-art wind-driven rain assessment models

and comparison based on model theory. Building and Environment, 45 (3): 691-703. •  Morrison Hershfield Ltd. 1996. Survey of building envelope failures in the coastal climate of British

Columbia. Report for Canada Mortgage and Housing Corporation, Ottawa, Ontario. •  Straube, J.F. and Burnett, E.F.P. 2000. Simplified prediction of driving rain deposition. Proceedings of

International Building Physics Conference, Eindhoven, September 18-21, pp. 375-382. •  Tariku, F., Cornick, S.M., and Lacasse, M.A. 2007. Simulation of wind-driven rain effects on the

performance of a stucco-clad wall. Proceedings of Thermal Performance of Exterior Envelopes of Whole Buildings X International Conference, Clearwater Beach, Florida, December 02, pp. 1-15.

•  TenWolde, A. 2008. ASHRAE Standard 160 P-Criteria for Moisture Control Design Analysis in Buildings.

ASHRAE Transactions, 167-171.

Buildings for Tomorrow Conference – Toronto Canada - October 28-30, 2014

14th Canadian Conference on Building Science and Technology 30

What’s Next?

Buildings for Tomorrow Conference – Toronto Canada - October 28-30, 2014

14th Canadian Conference on Building Science and Technology 31

Acknowledgement

• BCIT

• Concordia University

• NSERC Canada

• Staffs at BCIT: Doug Horn, Wendy Simpson, Tim Lee and Jordan Ho

Buildings for Tomorrow Conference – Toronto Canada - October 28-30, 2014

14th Canadian Conference on Building Science and Technology 32