Wind Pressures on Buildings

Questions and Answers

What is one of the two significant mechanisms that can lead to water being forced through walls and windows?

Capillary action

Pressure difference acting across a sealed joint (correct)

Evaporation

Thermal expansion

The kinetic energy of air-borne droplets in fast-moving air can prevent water from penetrating an open joint.

False

What principle does cladding that is designed for pressure-equalisation rely on to manage water penetration risks?

Pressure equalisation

Water is forced through openings and joints by mechanisms such as pressure difference and the kinetic energy of __________ droplets.

air-borne Signup and view all the answers

Match the following concepts to their descriptions:

Air Permeability = The ability of air to flow through a material Rainscreen Design = A system to manage water penetration while allowing drainage Cavity Pressure Management = Balancing pressures in wall cavities to prevent water intrusion External Wind Effects = Impact of wind on building walls and windows Signup and view all the answers

Which Technical Note discusses issues relating to wind loading on tall buildings?

TN 4 Signup and view all the answers

What is one of the primary functions of tiled roofs in relation to air flow?

Stop gross air flow between the tiles Signup and view all the answers

The wind pressure on the external face of the building remains completely constant over time.

False Signup and view all the answers

What two types of pressure management designs do modern rainscreen facades typically have?

Drained-and-ventilated and pressure-equalised Signup and view all the answers

The analysis of the movement of air into and out of a cavity as a result of pressure variations is known as _____ movement.

complex Signup and view all the answers

Which of the following methods can improve the effectiveness of preventing water penetration?

Properly sealing all sides and allowing drainage Signup and view all the answers

Match the following terms with their corresponding descriptions:

Drained-and-ventilated = Walls designed to allow drainage of water Pressure-equalised = Designs that balance pressure differences Water penetration risks = Potential entry of water through construction openings Air permeability = The ability of air to flow through materials Signup and view all the answers

Overlapping joints between tiles can help minimize water penetration.

True Signup and view all the answers

What is the primary purpose of the roofing felt beneath tile roofs?

To stop gross air flow between the tiles Signup and view all the answers

What occurs if the cavity compartments are sufficiently small?

Air pressure within them remains almost equal to external wind pressure. Signup and view all the answers

Positive external wind pressures occur only at the edges of a building.

False Signup and view all the answers

What does rapid pressure-equalization prevent in the cavity?

Water from being carried through and into the cavity. Signup and view all the answers

External wind pressures vary in magnitude from a peak positive pressure at the ______ face.

windward Signup and view all the answers

Match the following external wind effects with their descriptions:

Positive pressure = Occurs at the center of the windward face Negative pressure = Greater magnitude near the corners of adjacent sides Cavity air movement = Occurs from high to low-pressure areas Pressure-equalization = Prevents water carry-through Signup and view all the answers

Why is cavity volume an important factor in pressure management?

It affects how quickly air can move through the cavity. Signup and view all the answers

Air will always be drawn through non-compartmentalized cavities at a low velocity.

False Signup and view all the answers

What is the primary risk associated with water penetration in rainscreen design?

Compromise of building integrity or damage to interior spaces. Signup and view all the answers

Study Notes

Introduction to Pressure Equalisation

Pressure-equalisation is crucial for managing water penetration through walls and windows in wind-loaded structures.
Water can enter through joints via pressure differences or kinetic energy from moving air.

Mechanisms of Water Penetration

A pressure difference across a closed joint can push water through.
Fast-moving air can carry airborne droplets through open joints, necessitating well-constructed overlaps in cladding.

Cladding Constructed on Pressure Equalisation

Pressure-equalisation cladding utilizes air cavities effectively sealed to prevent water penetration while allowing drainage.
Ensuring cavity seals while allowing drainage at the bottom enhances effectiveness against water intrusion.

Wind Pressure Variation

Wind pressures can vary significantly over short durations, often changing within 0.1 seconds.
Building design must account for varying wind pressure, while structural safety factors typically involve a constant wind pressure.

Cavity Air Movement

Positive and negative wind pressures affect adjacent building faces simultaneously, inducing airflow through non-compartmentalised cavities.
Cavity design should ensure rapid equalisation of internal air pressure to prevent water ingress through joints.

Cavity Volume and Pressure Dynamics

Small cavity compartments help equilibrate air pressure with external wind pressure, reducing the chance of water being drawn into the structure.
Proper compartmentalisation is essential in maintaining pressure equalisation and minimizing potential water intrusion.

Rainscreen Facade Designs

Modern rainscreen facades are either drained-and-ventilated or pressure-equalised to mitigate water ingress.
Drained-and-ventilated designs incorporate openings for water drainage while maintaining air flow stability in cavities.

Key Design Principles

Proper sealing of air cavities enhances performance against water penetration.
The overall effectiveness of pressure-equalisation in cladding is improved with careful design and testing, as outlined in regulations and standards.

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Description

Explore the impact of wind pressures on building design and the critical role of pressure equalisation in preventing water intrusion. This quiz covers the dynamics of wind pressure variations and modern rainscreen design. Test your knowledge of how external forces influence architectural stability.

Wind Pressures on Buildings

Questions and Answers

What is one of the two significant mechanisms that can lead to water being forced through walls and windows?

The kinetic energy of air-borne droplets in fast-moving air can prevent water from penetrating an open joint.

What principle does cladding that is designed for pressure-equalisation rely on to manage water penetration risks?

Water is forced through openings and joints by mechanisms such as pressure difference and the kinetic energy of __________ droplets.

Match the following concepts to their descriptions:

Which Technical Note discusses issues relating to wind loading on tall buildings?

What is one of the primary functions of tiled roofs in relation to air flow?

The wind pressure on the external face of the building remains completely constant over time.

What two types of pressure management designs do modern rainscreen facades typically have?

The analysis of the movement of air into and out of a cavity as a result of pressure variations is known as _____ movement.

Which of the following methods can improve the effectiveness of preventing water penetration?

Match the following terms with their corresponding descriptions:

Overlapping joints between tiles can help minimize water penetration.

What is the primary purpose of the roofing felt beneath tile roofs?

What occurs if the cavity compartments are sufficiently small?

Positive external wind pressures occur only at the edges of a building.

What does rapid pressure-equalization prevent in the cavity?

External wind pressures vary in magnitude from a peak positive pressure at the ______ face.

Match the following external wind effects with their descriptions:

Why is cavity volume an important factor in pressure management?

Air will always be drawn through non-compartmentalized cavities at a low velocity.

What is the primary risk associated with water penetration in rainscreen design?

Study Notes

Introduction to Pressure Equalisation

Mechanisms of Water Penetration

Cladding Constructed on Pressure Equalisation

Wind Pressure Variation

Cavity Air Movement

Cavity Volume and Pressure Dynamics

Rainscreen Facade Designs

Key Design Principles

Studying That Suits You

Description

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