Group 5.2 - Window and Door Installation: Sealants. Flashcards
Sealants used in the factory are listed in what standard?
AAMA 800
Most sealants used in the field for installation also listed in AAMA 800. What sealant types are included?
Exterior Perimeter Sealing Compound
Non-Drying Sealant
In addition to those listed in AAMA 800, additional sealants used in installation are found in what other standard, and what kind of sealants are referenced?
AAMA 812
Foaming Sealants
List some factors that need to be considered in sealant selection:
Joint movement
Characteristics that
- Adhesion and Cohesion
- Hardness and Elasticity
- Elastic Recovery
- Permanent Set
- Compression Set
What are the two joint configuration types?
Working (moving) Non Working (fixed)
Working joints are classified as either:
2
Butt or
Lap joints
(or a combination of the two)
Sealant joint must maintain is sealing characteristics despite movement due to these causes:
(4)
thermal differentials
wind load,
settling of the structure,
seismic activity
or other sources.
How is joint movement expressed (numerically)?
In fractions of an inch.
AAMA recommends what design factor with regard to joint movement? What does this mean?
4:1
The joint should be sized at 4-times the amount of movement expected.
This primary source of joint movement depends heavily on the materials involved.
Thermal expansion and contraction.
This material attribute relates to the amount of thermal expansion to be expected from that material?
Coefficient of Linear Expansion
Sealants are assigned into classes, based on their ability to handle extension or compression per this standard:
ASTM C920
Sealant classes assigned per ASTM C920 are based on:
c. the weathering characteristics of the s
The amount of movement (+ or -) that the sealant can accommodate
Sealant classes per ASTM C920 include:
\+/- 12.5% \+/-25% \+/-35% \+/-50% \+/-75% \+100% - 50%
Applications where flashings or fins are bedded in sealants are what type of joint?
Lap joints (low movement).
To achieve good adhesion, a _____ is often required to be applied to the substrate.
Primer
Peel adhesion test method for adhesion between glass and metal is defined by what standard?
ASTM C1135
Indications of sealant incompatibility include:
CATS BEC
Think about what can be seen, touched and tested.
COLOR changes
ADHESION loss
increased TACKINESS
SOFTENING
Bleeding
Embrittlement
lack of CURE
What standard spells out required performance parameters for installation sealants?
AAMA 800
AAMA 812
ASTM C1248
AAMA 701
AAMA 800
How many types of laboratory tests are included in ASTM C1248 test for porous substrate staining?
Four
This standard covers four types of laboratory procedures to test for staining of porous substrates by sealants:
ASTM C920
AAMA 800
AAMA 812
ASTM C1248
ASTM C1248
What AAMA standard covers pumpable or gunnable compounds that remain ductile or elastic, and permit moderate movement without loosing adhesion?
AAMA 800
AAMA 812
AAMA 808.3
AAMA 701
AAMA 808..3
AAMA 808.3 includes __(qty) performance parameters and testing methods to verify sealants’ performance by those parameters.
2
8
12
20
Eight
There are 8 primary sealant performance characteristics evaluated by AAMA 808.3. List four:
(Think about visible and performance testing parameters and practical concerns)
Visual - no cracks after heat and UV.
Hardness Shore A 55 or less
Peel adhesion at 5lbs / inch of width
Slump < 1/10 in 5 minutes
Vehicle migration - No VM after 14 days at 180
Low temp flexibility - no cracking at 7 degrees
Staining: No Discoloration of conc. or wood (140 deg & water immersion)
Water resistance - no voids after 14 days immersed at 180 F.
This standard covers gunnable compounds for sealing buck frames and thresholds which remain tacky throughout the service life.
AAMA 809.2
Performance parameters for non-drying sealants per AAMA 809.2 (AAMA 800, section 5) include which four of the following?
Visual Screening Peel Adhesion Test Flex - Low Temp flexibility Staining on wood and concrete Water resistance Slump Shore 'A' hardness Elongation
(Similar to 808.3, minus 4 - VFWS)
Visual Screening
Flex - Low Temp flexibility
Water resistance
Slump
Aerosol foam sealants should be carefully selected to avoid this concern specific to this sealant type:
over-swelling of the foam and deformation of the window or door frame.
This AAMA standard addresses specific installation and material concerns for aerosol foam sealants.
AAMA 812
The two key material attributes that contribute to deflection of fenestration products as identified in AAMA 812 are:
Expansion ratio and pressure build
Cellular structure and dimensional stability
Expansion ratio and cellular structure
Pressure Build and Dimensional Stability
Pressure Build
Dimensional Stability
What does pressure build measure?
Maximum pressure over time that the foam can exert.
The criteria for evaluating dimensional stability of aerosol foam sealants, included in AAMA 812 references an industry standard maximum of __ % variation in thickness after initial cure. The test requires conditioning three cured samples at temperatures of ___, __, and __ respectively.
Measurements of foam expansion on each sample are taken after ___day and ___days in conditioning chambers.
(Temps are C or F equivalents)
No more than 10% variation After heating at 104 F _ 40 C 86 F _ 30 C -4 F _ -20 C
at 7 and 14 day intervals
What are the criteria that the installer must consider in selecting and applying sealant?
(MACPP)
joint MOVEMENT (anticipated amount and sealant capacity) Adhesion Compatibility Primers Preparation.
Joint backing provides 4 primary advantages for sealant installation and performance.
- Controlling the ___ of the sealant.
- Developing a ____ bead shape
- Support for sealant _____.
- Acts as a ____ ______.
Control depth/width
Develop concave bead shape
Support Tooling
Serve as bond breaker
If a closed-cell backer rod is used behind a sealant installation, care should be taken to avoid____.
Why?
Punctures.
Escaping gas can cause blisters in the sealant.
Backer rod should be __% larger than the joint width.
25%
Sealant should bond ___ to the backer rod.
Moderately
Tenaciously
Very little / Not at all
Not at all.
Where the joint assembly include a tongue or back-plate behind the joint, without enough depth for backer rod, add___ behind the sealant prior to installation.
Bond-breaker tape
A butt joint sealed at the ____ end of the actual service temperature will always be in tension.
Coldest, lowest
Sealant should be installed when the temperature of the assmebly is at it’s
Coldest
Hottest
middle range.
Middle.
For most applications, a ____ shaped sealant bead should be installed
Triangular
Hourglass
Pretzle
Hourglass
If you said pretzle, your fired, or hungry or both.
A sealant joint should be ___ times as wide as it is deep.
Two times.
Width should be twice the depth but depth should not be less than 1/4” in most cases.
5.2 Quiz
1. Which of the following is not addressed in AAMA 800?
Exterior perimeter sealing compound
non-drying sealant
foaming sealant
pumpable or gunnable compounds
foaming sealant
5.2 Quiz
2. Which of the following is not addressed in AAMA 812?
Pressure build
Dimensional Stability
Non-Drying sealant
Foaming sealant
Non-drying sealant
5.2 Quiz
3. A bond breaker:
prevents three-sided adhesion
permits damaged sealant to be easily removed
permits cohesive failure only
eliminates the need for backer rod
prevents three-sided adhesion
5.2 Quiz
4. Mfr. instructions should always be followed; but generally, backer rod should be selected _____width of the joint to be sealed.
slightly smaller than
equal to
10% larger than
25% larger than
25% larger than….
- 2 Quiz
- Because sealed joints experience movement due to thermal expansion and contraction, joints sealed at a very low temp will ____ when the temp rises.
Stretch the sealant
compress the sealant
tend to shear the sealant
fail
Compress the sealant.
This is a bit tricky, if you picture things expanding as the assembly heats it’s easy to initially imagine this will expand the joint. It won’t - the expansion to both sides will compress the joint.
Read the questions carefully.
