1. 1
ThermArk
A Low Cost Thermal Insulation for Humanitarian and Disaster Relief Services
MSE 4410-A1
Instructor: Dr. Sundaresan Jayaraman
Group: Kinsey Canova, Erin Flynn, Jarad Heimer, Tyler Rice
Georgia Institute of Technology
North Avenue NW, Atlanta, Ga 30332
3. 3
Executive Summary
In the city of Atlanta, Georgia, emergency shelters provide safe and warm sleeping
environments for approximately 3,280 of those less fortunate in times of life-threatening
environmental conditions [1]. Unfortunately, as of 2015, the total homeless population of Atlanta
(the sum of those in living emergency shelters and those living on the street) was approximated at
4,317 people, leaving 1,037 men, women, and children truly homeless living on the street [1]. With
December rapidly approaching, the grips of winter will set in and put those 1,037 homeless
individuals in cold weather-induced, life-threatening environments every night and day. Similarly,
those affected by disaster in the winter months require similar protection due to loss of artificial
heat production or shelter.
The current methods of protecting these individuals rely on the donations or purchase of
protective clothing and blankets to charity or government-funded programs as “Church on the
Street” or FEMA respectively. Specifically for the homeless, layers of clothes and blankets do not
provide adequate protection from wind, rain, other wintery precipitation. These conditions lead to
wet clothing and blankets, inducing 20x more body heat loss than the dry alternative [2]. This
increases the potential of hypothermia and other cold-weather afflictions such as frostbite. To limit
this concern, the product must be waterproof and windproof. The product must also be thermally
insulating, transportable, durable, gouge-resistant, easy to clean, and cost-effective. The cost-
efficiency is required so humanitarian and disaster relief agencies can afford to purchase and
rapidly distribute the product at critical times. Cost is the current limitation, since consumer
products, such as the Bivy, fulfill all of these needs but costs between $40 and $500 per unit. On
the cost-effective side, foil blankets or foil sleeping bags keep the user warm and isolated from the
harsh environment for under $3 a unit but lack durability due to tearing [3].
The primary market for this product is relatively large in the United States with an average
of 3.5 million American being temporarily or permanently homeless on any given night due to
disaster or permanent homelessness [4]. Though the lucrative nature of the primary market is
limited due to a combination of charitable use and subsequent low required manufacturing and
distribution costs, profitability is possible due to the market size and the sales into such secondary
markets as camping equipment, which, is projected to be a $5 billion market by 2019 [5].
The user needs and market research led to the development of a final product concept of
ThermArk, which combines all of the positives from the current products such as the Bivy or the
common donated blanket but without the high cost or lack of protection from wet and windy
conditions. This is achieved through a robust, multilayered low density polyethylene (LDPE)
covering containing button snaps to seal the user from the harsh external environment. Flexible
LDPE foam provides thermal insulation and padding while external and internal thermally-adhered
sheets of LDPE provide abrasion resistance and heat reflectance via vapor-deposited aluminum on
the internal LDPE sheet. The use of one material, LDPE, reduces costs and limits environmental
impacts due to the ease of ability to recycle and/or downcycle components at end of life. With the
help of ThermArk, the homeless and those stricken by disaster can sleep soundly, knowing they
will stay protected from the harsh winter environment in their moment of need.
4. 4
Introduction
Background
On January 28, 2014, “Snowpocalypse” descended on the city of Atlanta [1]. There was a
general hysteria as people rushed to the warmth and comforts of home to ride out the
storm. However, some people had no home to go to. On any given night in the state of Georgia,
approximately 6,000 individuals sleep unsheltered [2]. There are not enough shelter beds to go
around, and not everyone is eligible for temporary housing. Therefore, hunkering down and
fighting the elements is the only option available. However, surviving exposure to
prolonged subfreezing temperatures, severe wind chill, and several inches of snow is difficult
even for those trained in survival. For those with limited supplies and no formal survival training,
it is nearly impossible. Hypothermia deaths among the homeless are common in the winter; 700
people die annually in the US from hypothermia simply because they are homeless [3]. It does
not need to be snowing, windy, or subfreezing for hypothermia to set-in; hypothermia cases have
been reported at temperatures as high as 50°F [3]. Homelessness in a developed country like the
United States should not be a death sentence.
The current methods of warmth available to the homeless include emergency winter
shelters, traditional blankets, and makeshift shelters. The best of these are the winter shelters
which open when temperatures drop below freezing. The shelters protect the homeless from the
severe elements of wind and precipitation; however, these shelters have many drawbacks
that stop them from being effective at preventing hypothermia deaths. The primary shortcoming
is the lack of space; each shelter has finite space and once these spaces are filled, anyone else is
turned away. Additionally, the shelters are usually just a large stone room filled with
many people; they are often loud, drafty, and not necessarily heated. For those unable to get into
a shelter, blankets and makeshift protections are often the only alternative. Blankets,
although readily available, are bulky and permeable by water and wind. Any make-shift
protections are often only effective at partially blocking wind and precipitation. The insulation
provided by blankets or a partial-shelter is often not enough to protect the person when
temperatures stay below freezing for an extended period of time.
Technologies exist to protect people from harsh elements and cold, but many of these
are expensive and not readily available for those experiencing homelessness. A Bivy is a hybrid
of a sleeping bag and a tent that boasts full body insulation capabilities. However, even a
cheap Bivy usually costs $60, which is far too expensive for a homeless person. Insulating
emergency shelters used by disaster relief agencies like the Red Cross are also expensive as well
as too bulky and flashy to be used by those experiencing homelessness. There is a need for an
insulating shelter to be available to homeless people during harsh weather and the goal of this
project is to fulfill that niche.
Mission Statement
Initial development of the mission statement focused on helping add insulation to
makeshift shelters the homeless may already have, such as cardboard boxes, tarps, or overpasses.
Initially proposed product benefits suggested the product “would use adhesive on the back of
the insulator to be able to stick to whatever structure is being used to provide shelter.” However,
research found that this solution may not be practical for many of the homeless population. The
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homeless frequently move around, which would require removing the adhesive insulation from
one structure and adherence to another structure over multiple iterations. Additionally, homeless
do not always have a makeshift shelter, so the benefits of an adhesive would not be realized. After
learning these realities, the mission statement evolved to focus on developing a standalone product
that would protect the user from the elements and the cold temperatures.
The product developed is aimed primarily at helping the homeless. The idea is that the
product would have low enough cost that charities and aid groups would be able to purchase it in
bulk and distribute it among the homeless. However, the functionality of the product could also
be used in emergency situations, such as by those stranded in blizzards or displaced by floods.
Thus, this product could be a component of emergency kits or distributed by disaster relief
agencies. The design process focused on the needs of the homeless due to their need for such
protection being more eminent and extending for a longer period of time. The final mission
statement guiding product design is shown in Figure 1.
Figure 1: Product mission statement
Concept Generation
User Needs
Due to the nature of the project, conducting interviews of the primary users was infeasible.
Instead, interviews of those who interact with the homeless on a regular basis was done. These
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three were Pastor Andy Odle, who works for Church on the Street, and Marc Smith and Paige
Hoerle, who both work for Christian Campus Fellowship at Georgia Tech. Both of these
organizations do outreach programs to assist the homeless, and interview with them revealed that
the mission statement suggesting adhesive for a structure needed to be changed to fit the new user
needs. The final user needs can be found in Table 1. This process taught that it is important to
survey user needs before developing a mission statement, especially when the primary market is
unknown.
Table 1. User Needs
Needs
Thermally insulating et. al. Breathable
No risk of suffocation Meets restrictions set by locality
Thermal protection against ground Locking mechanism
Waterproof Simple packing
Windbreaker/Wind-proof/resistant Lightweight
Low-cost Packable to fit in small volume
Endures one month of use Convenient to carry
Can be cleaned May be carried in mass transit systems
Retains functionality when abraded etc. Survives opening and closing
Gouge resistant Breathable
Discreet Spatially efficient
Able to see surroundings from inside Expandable
Antimicrobial Comfortable
Along with gathering user needs, interviews allowed for clear identification of the lead
customers and what issues they would encounter. It was learned that there are three types of ways
to sleep when you are homeless: in a shelter; unsheltered on the streets or in the park, also known
as rough sleepers; and tent cities, typically outside of the city away from public spaces where many
people can set up camp. The product’s main goal is to help all these types of sleepers by making
it easily portable, lightweight, low cost, resistant to the cold and other extreme temperatures, water
resistant, easily cleanable, and discreet.
Supergroups (ITYs)
Once user needs were gathered, they were organized into supergroups (ITYs), in order to
simplify future prioritization of the needs. The user needs were grouped into seven ITYs which
were functionality, affordability, durability, portability, safety, reliability, and usability. ITYs were
individually defined to ensure consistency when assigning user needs to those groups. The ITY’s
and user needs are shown in Figure 2.
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Figure 2: ITY's and User Need Assignments
Functionality was defined as the product allows the user to endure and survive the cold
seasons and subsequent associated environments. This ITY was populated with user needs that
were are necessary to keep the user warm and separated from harsh environmental impacts. These
needs are interdependent and require each need to be fulfilled for the product to efficiently
function. For example, if the product was not windproof then it would have ideal thermal insulating
capabilities due to the penetration from the wind and subsequent conductive cooling. These user
needs parallel the mission statement to clearly identify that, if the final product does not fulfill the
needs within the functionality ITY, the product does not align with the mission statement and
requires revision.
A second key point in the mission statement was to create a product that was affordable to
humanitarian and disaster relief organizations; this led to creation of the affordability ITY.
Affordability was defined as “the product can be produced and distributed for minimal cost to the
user.” The only user need that is associated with affordability is cost. Cost includes the sum of the
raw material, manufacturing, distribution, and wholesale expenses that are passed on to the
consumer. Affordability and the user need of cost is paramount and, if it is not upheld, the product
will not be able to be purchased and distributed to those less fortunate.
Durability was defined as “the product functioning adequately over its lifetime.” This ITY
contains the needs of endure at least a month of use, can be cleaned, functions when abraded, and
gouge resistant. The need to endure at least one month of use defines the minimum length of time
the user expects the product to function. One month of use allows a user in Georgia to survive the
coldest period of the year. With consistent use on the streets, the product may come in contact with
rocks, glass, and other damaging materials that may abrade and permanently damage the product.
This is why the product must consist of a material that resists gouging or, if damaged, provides the
same functionality as before gouging. The last need within this ITY was the requirement that the
product has chemical stability and acceptable resistivity to a wide range of chemicals and solutions.
This allows the product to be cleaned with common household or commercial chemicals.
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Since the user may be constantly on the move, an ITY that encompasses all of the needs
which associate with traveling was created. That ITY, portability, was defined as “the user can
travel as needed while transporting the product.” Interviews indicate that many homeless carry
their sleeping materials in a backpack or bag, which set specifications for user needs. One of the
issues that some homeless have is the fear of sudden and rapid evictions from their sleeping or
camping spot. If the eviction happens, the user must be able to quickly gather their belongings or
face civil penalties. To mitigate that fear, the product must have a simple packing scheme that can
be executed rapidly and efficiently.
Safety was designated as an ITY for all of the user needs that fall under the definition of
“the product introduces no new threats to the user.” Due to local laws and ordinances such as the
Urban Camping Ordinance in Atlanta, the user has to be vigilant of the surrounding and not draw
attention to his or herself. If the user cannot see his or her surroundings or the product draws
attention instead of being discreet, the user has an increased chance of violating the local laws and
ordinances. Due to the potential danger caused by other humans, a locking mechanism may be
desired to increase personal safety. One of the largest safety concerns is the ability of the user to
breathe within the product. If the product gives off chemical odors or does not permit air exchange
with the outside environment, the user could suffocate. Another safety-based need is, if the
surfaces of the product are not antimicrobial, then the user may see increased chance of infection,
uncomfortable odors, and/or untimely degradation of the product.
Reliability was defined as “the product functions effectively when the need for use arises.”
Though reliability and durability seem similar, reliability requires that the product functions as
expected with every use while, durability is retaining functionality over time. The only user need
assigned to reliability was survives opening and closing. This was assigned to reliability since,
without the use of an opening or closing mechanism, the product would not be able to effectively
seal the user from the cold harsh environment.
The final ITY, usability, was defined as “product can be used with comfort and
convenience.” This encompassed the needs which are all predominantly "wants," not
requirements. The need comfort defines how the product material feels to the user, specifically the
cushioning of the sleeping surface, when in use. The need for expandability relates to comfort; an
increase of internal surface area when the product is in use increases the amount of space to move
around. This makes the product feel less restrictive and more comfortable to the user. Breathable,
in this context, considers how comfortable it is to breathe the air when using the product. For
example, a high internal humidity will make sleeping in the product uncomfortable and more
difficult due to the air being more difficult to breathe. If excess design focus is put on comfort and
non-vital parts, the product may quickly increase in cost. Spatial efficiency was chosen to keep the
product affordable to the user/consumer. Spatial efficiency is the lack of excess material or
addition of non-vital survival aspects on the product.
Prioritization Matrix
As the design process continued, a ranking method was used to determine which
supergroups and needs take precedent over others. This was a vital part of the design process since
it defined what needs and supergroups would be higher priority when discussing future trade-offs.
Prioritization matrices were conducted on two levels. The first was based on the ranking of the
individual ITYs against each other and the second was a ranking of the user needs within each
ITY.
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The prioritization matrix for the ITYs, Figure 3, was determined through ranking the
importance of each ITY against each other. The comparison method was conducted on a scale of
0.10, 0.20, 1, 5, and 10. A designation of 1 between two ITYs signified that they are of equal
importance, 5 signified that the ITY in the top row was slightly more important than the ITY in
the side column, and 10 signified that an ITY was significantly more important than the other.
Designations of 0.10 and 0.20 are, respectively, inverses of the designation of 10 and 5. The
prioritization matrix showed that functionality and affordability were determined as equal and
were the highest priority, as expected, followed by durability, safety, portability, reliability, and
usability. The matrix yielded a surprisingly low rating for usability. This rating was the result of
the definition of usability and the input received from the three interviews conducted which, stated
that comfort is not significant factor when concerning life and death situations. A comfortable
product may lead to pushback by charities since their ultimate goal is to transition the homeless
from street or "rough" sleeping to a more permanent housing situation. Comfortability may inhibit
the desire to improve the situation at hand and create a larger homelessness issue. These
prioritizations were later utilized within the other ranking matrices such as the concept and material
decision matrices.
Figure 3: ITYs Prioritization Matrix
The second level of the prioritization matrix is the ranking of the user needs within each
individual ITY. These were conducted to determine which user needs within each ITY should be
considered higher importance to design. The prioritization matrices for each ITY can be referenced
in Appendices A1-5. It should be noted that prioritization matrices for reliability and affordability
were not created since each of those ITYs contained only one user need.
Needs-Metrics Matrix
The next step towards concept development was the assignment of metrics to the user needs
that were previously identified. Each need was defined by at least one metric in a quantifiable,
qualitative, or subjective manner; this is shown through the needs-metrics matrix in Figure 4. The
common downward linear trend is present in the matrix with deviations due to a metric assigned
to multiple needs. As development of the product progressed, the need-metrics matrix concurrently
evolved due to feedback from other groups, instructors, and new research. The first iteration of the
matrix yielded metrics that were vague and could not be properly quantified. For example, the
current metrics of length, width, and height were grouped into a single metric called "Can fit an
average to large sized person." The older metric was vague since it was an agglomeration of three
separate and vital design metrics. Following a project progress review, the needs-metrics matrix
was altered and refined to add the needs of "can be cleaned" to the durability ITY and antimicrobial
to the safety ITY. Metrics of chemical resistance and microbial growth were assigned to the "can
be cleaned" and antimicrobial needs respectively. These new needs and metrics were added as a
ITY Functionality Usability Durability Safety Portability Affordability Reliability Sum Normalized (%)
Functionality 10 5 1 5 1 5 27 23.94%
Usability 0.1 0.1 0.1 0.2 0.1 0.2 0.8 0.71%
Durability 0.2 10 1 1 0.2 5 17.4 15.43%
Safety 1 10 1 0.2 0.2 5 17.4 15.43%
Portability 0.2 5 1 5 1 5 17.2 15.25%
Affordability 1 10 5 5 1 5 27 23.94%
Reliability 0.2 5 0.2 0.2 0.2 0.2 6 5.32%
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measure of the health and safety of the user since the homeless or victims of disaster may not be
able to clean themselves or their clothes. The lack of cleanliness allows for dirt, microbes, and
other contaminants to accumulate on the inside of the product and can lead to increased risk of
infection or other health concerns. Depending on the type of microbe present, the mechanical
integrity of the product can be decreased as well. The ideal and marginallyacceptable metric values
corresponding to their verbal descriptions can be found in Appendix C4.
Figure 4: Need-Metrics Matrix for ThermArk
Initial Concepts
The completion of a needs-metrics matrix and the ideal/marginally acceptable values
(Appendix C4) led to the development of initial concepts. Concept generation occurred in two
stages: 1) development of concepts that fulfilled each ITY and 2) organization of each concept into
subgroups of structure, insulation, and closing mechanisms. The concepts from stage one were
discussed within the group to determine which concepts were plausible and easily produced. The
remaining concepts were organized into the sub-concepts in stage two.
Structure
The first sub-concept was concerned with the development of the structure or skeleton of
the product. The five concepts that were created were coined "livable laundry basket", "accordion
style", "garage door", "Bivy-style", and "intense sleeping bag.”
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
Need
Metric
ThermallyInsulating
InternalTemperature
Breathable
Water-Resistance
Wind-breaking
ConsumerCost
CosttoManufacture
CostofDistribution
PercentRecycledMaterialsUsed
Chemicalresistance
Lifetimeofproduct
UseCyclesuntilfailure
YieldStrength
GlassTransitionTemperature
Loadrequiredtoopen
Visibilityofuser
InternalHumidity
UserVisibility
MicrobialGrowth
Legality
Stepstobreakdown
Timetobreakdown
Nounusedmaterialonproduct
Volumewhenpacked
Weight
FollowsrulesforMARTA,bus,etc.
ConducivetoSleep
Length
Width
Height
SoundDampening
1 Thermally insulating et. al. x x
2 No risk of suffocation x
3 Thermal protection against ground x x
4 Waterproof x
5 Windbreaker/Wind-proof/resistant x
6 Low-cost x x x x
7 Endures one month of use x x x x x
8 Can be cleaned x
9 Functions when abraded etc. x x
10 Gouge resistant x x
11 Discreet x
12 Able to see surroundings from inside x
13 Antimicrobial x
14 Breathable x x
15 Meets restrictions set by locality x
16 Locking mechanism
17 Simple packing x x
18 Lightweight x x
19 Packable to fit in small volume x x
20 Convenient to carry x x x x
21 Carry in mass transit systems x x x x
22 Survives opening and closing x x x x
23 Breathable x x x
24 Spatially efficient x x x x x
25 Expandable x x x
26 Comfortable x x x x x x
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The livable laundry basket, Figure 5, was modeled after the cylindrical laundry baskets that
contain a spiraled, flexible polymer or metal frame. This concept allows the user to rapidly deploy
the product by allowing the material-coated spiral frame to expand. When required to travel, the
user brings the ends toward each other to compress the internal spiral frame. The cylindrical
volume allows ample space when in use and compact profile when not. Drawbacks from this
concept include limited expandability and need for different materials in frame and material
between.
Figure 5: Drawing of the livable laundry basket concept
Similar to the livable laundry basket, the accordion style concept, Figure 6, folds up via
end-caps. The main differences are that the structure is a rectangular prism and is sectioned by
rigid, open-networked square frames. An insulating material is attached to each of the square
frames to create the accordion-like design. The rectangular prism shape allows the user to be
situated on a flat surface instead of the unstable curvature of the cylindrical laundry basket concept.
This structure has similar drawbacks to the livable laundry basket with the additional need for
reinforced frame corners.
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Figure 6: Drawing of the accordion-style concept
The garage door concept, Figure 7, was designed to look like a common mat but contains
a hidden compartment at the bottom: a covering which can be pulled over the mat. This covering
contains joints that allow for the covering to fold and unfold quickly as well as create a self-
supporting protective structure over the user. The mat allows for comfort and thermal protection
from the ground while the covering protects the user from wind, precipitation, and the cold air.
Folding a unit along its length would be hindered with this concept, and extra design is required
for the joints along the movable cover.
Figure 7: Drawing of the garage door concept
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A Bivy-style product, shown in Figure 8, would be a combination of a "tent" near the head
and a sleeping bag. It is designed to have lightweight supports or self-supporting, semi-flexible
material to keep the device off the face of the user. This raised material in the head area allows the
user to not feel entrapped by the product thus potentially improving the comfort, spaciousness, and
breathability of the product. Trapped air near the head area provides additional insulation. A
primary challenge with this architecture is that users may not understand how to construct the head
area of the product.
Figure 8: Drawing of the Bivy-style concept.
Unlike the previous four sub-concepts, the intense sleeping bag, Figure 9, contains no
internal framework and would be similar to a sleeping bag. The main difference to current product
is that the product would include a translucent viewing window to see out of and will be breathable
when sealed. This concept allows for a variety of user configurations, such as a blanket or enclosed
sleeping bag, to satisfy needs regardless of ability to assemble a structure. Locking components on
the sides can be used or ignored by the user.
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Figure 9: Drawing of the intense sleeping bag concept. The top view depicts the concept when
not sealed and in a blanket-like form.
Insulation
Concept generation for the insulation sub-concept yielded the five concepts coined
"Alternating Rings of Vacuum and Foam", "Water-Resistant Liner", "Emergency Blanket Liner",
"Heat Reflective Layer", and "Multi-Layer."
The "Alternating Rings of Vacuum and Foam" was designed to incorporate the heat
transfer damping potential of a system in vacuum. The structure would be comprised of insulating
foam with alternating vacuum-pulled rings down the length of the product. The vacuum sections
would allow for high thermal insulation, while the foam sections would allow for it to be
breathable. Isolating the sections from each other increases resistance to puncture.
As previously stated in this document, if the user clothes and/or protective device is
inundated with water, the ability to retain body heat is reduced almost 20 times. This requires an
insulation with a resistance to water permeation. The "Water-Resistant Liner" concept includes a
hydrophobic liner on the outside and inside of the product with insulating foam between. This
allows for protection from snowy or rainy outside environment and to ensure the foam does not
become inundated with water that may have accumulated on the user’s clothes and belongings.
The internal hydrophobic liner also allows the product to be easily cleaned, improving safety.
Emergency blankets, also known as Mylar or space blankets, are currently utilized in
emergency situations to partially cover, insulate, and reflect heat from the user when facing a
hypothermia-inducing environment. These are commonly standalone and are composed of vapor-
deposited metal on two thin polymer sheets that are adhered together [8]. The emergency blanket
liner would be thicker version of a standard Mylar blanket that is attached to the inside of the
structure. This liner would extend the length of the product and line the areas of the product that
typically line up with the greatest level of radiant heat generated from the body. This allows for
the overall product to be breathable since Mylar typically does not allow air permeation.
15. 15
Similar to the emergency blanket liner, a "Heat Reflective Layer" would be composed of a
material that reflects the user’s radiant heat. This method uses thin, flexible metal films to
accomplish this radiant heat reflectance. The metal film would be enclosed between two polymers
sheets containing a pocket of air. Sealing the metal film between two sheets protects the user from
the metal as well as protects the metal film from the environmental factors. This would be
distributed in a tight checkerboard-like pattern over the length of the product to allow for increased
breathability and effective radiant heat reflection.
The "Multi-Layer" design would be a combination of multiple insulation concepts and
materials to make an insulating layer. This design features a waterproof outer layer, a thermally
isolating foam core, and an inner layer composed of a water-resistant material coated with a
thermally reflecting material. The design is an agglomeration of the using a foam layer from the
"Alternating Rings of Vacuum and Foam", the water-resistant or hydrophobic layer from the
"Water-Resistant Liner", "Emergency Blanket Liner", and the heat reflective material used in the
"Heat Reflective Layer" concept. The multi-layer concept leads to protection from hypothermia –
inducing temperatures and water intrusion while adding a degree of comfort and support with
presence of the foam.
Closing Mechanisms
Closing mechanisms are sub-concepts that can be associated with the opening and closing
operations of the future product. Button snaps, zippers, and ties, were chosen as potential options
due to their cost effectiveness and successfulness in other products such as jackets. All of these
potential methods can allow for sufficient separation of the user from the outside environment.
Application of button snaps and ties would be strategically placed on the product to minimize
unnecessary material use but maximize closure. The tie concept is a simplified tie and loop method
where fibrous or braided materials create a loop on a side of the product. On the other side, a non-
looped piece of this material is tied to the loop to create a loose seal between the two sided. Like
buttons, this would have to be repeated several times on the product surface to allow for an efficient
seal from the environment. A zipper provides the most effective seal against the environment but
has a high potential to be critically damaged and thus lose functionality.
Concept Screening and Selection
Following identification of the sub-concepts, the strengths and weaknesses of each were
identified to determine which sub-concepts should be incorporated into the final design. Concept
ratings were conducted on a scale of one to five where, a score of one signified low fulfillment of
the needs while a five signified high fulfillment of the needs; a score of three was considered a
neutral rating. These ratings were multiplied by the weight of each supergroup to facilitate
comparison among concepts. The completed matrices for each sub-concept are found in
Appendices B1-3.
Following completion of selection matrices for each sub-concept, the overall concept was
configured. The sub-concepts of intense sleeping bag, multi-layer insulation, and button snaps
were combined to create an overall concept. The selection matrix for the structure sub-concept
yielded the intense sleeping bag due to its simplicity, potential ease of manufacturability, and
proven effectiveness in similar designs. The main concerns with the other sub-concepts were that
16. 16
increased complexity could yield more points of failure as well as rigid structures are less discreet
for homeless outside of shelters. The selection matrix for closing mechanisms yielded a tie between
ties and button snaps. Button snaps, such as in rain jackets, reliably close structures and effectively
seal a user from outside influences and were therefore chosen.
The only selection matrix that the group did not choose the highest-rated concept was for
insulation. This matrix yielded an insulator with a water-resistant liner as the choice. While this is
needed in the product, the group decided that a multi-layer insulator that combines water-proof,
heat reflecting, and windproof materials along with an insulating layer. The matrix discounted this
as a viable method due to a potential lack of portability due to a possible rigidity and weight
concern. The group decided that, through effective material selection and product architecture, the
final product will still retain a high degree of portability even with a multilayer insulation method.
Detailed Design/Concept Architecture
Material Selection
Material selection began with planning how the foam-fabric sandwich concept would be
realized. Research was divided into the functions this “sandwich” needed, such as a tough,
waterproof outer layer, foam for the inside, and a heat-reflective inner layer safe for prolonged
contact with the user. Materials used for snaps and the interface between the user and the ground
were also considered, as these have some requirements apart from the main insulating composite.
The importance of affordability for a product meant for the homeless guided materials research;
use of different materials for each layer would increase the price of the final product as economy
of scale would be diminished. Also, different materials would require different industrial controls,
such as processing temperature, and the chance of product defects would be increased.
Metrics gathered from research could not be directly applied to the metrics based on user
needs. In order to evaluate which material best satisfies the needs and metrics for our project, the
available values were related to which supergroup they apply to. For example, listed price in
USD/lb. was rated for satisfaction of the affordability supergroup. Ratings were done on a scale of
one to five, and the ratings were multiplied by the weight of each supergroup to facilitate
comparison among materials. Rated materials for each function are available in Appendix C1.
The initial material focused on which could satisfy all needs was poly (ethylene
terephthalate) (PET), since it could be cheaply processed into a solid sheet and a foam. Efforts
were made to fit PET to the user needs, such as packing the material into a small space. PET is
used to make camera film, so tightly rolling the material was possible. However, the outstanding
barrier for using PET was the polymer’s high glass transition temperature. This factor meant that
PET would be brittle at service temperatures. Also, tightly rolling the insulator would only work
to reduce size in one direction. To make progress, low-density polyethylene (LDPE) was identified
as a good material for making foam and was then considered for other functions. It was similar to
PET in price to make and process, and it would remain flexible at service temperatures. This
process taught the group to remain open-minded when choosing materials and provided experience
in considering transition temperatures as a factor in design.
LDPE was chosen above other candidate materials for how well it suits the user needs, and
its familiarity with consumers gives it tangible value. Plastic grocery bags are made from this
material, which allows research regarding safety and strength to be corroborated by personal
17. 17
experience. Thickness of outer and inner layers is based on thickness of LDPE bags, where sturdy
plastic bags make a good approximation for the durable outer layer’s thickness [9]. Common use
of LDPE also enables the product to be manufactured from mostly recycled LDPE. The product
can be washed with water to remove grime obtained during use; LDPE often chosen as a food
container due to its lack of reactivity with organic products [10].
The foam-sheet sandwich composite cannot fully insulate a person if that material needs to
pack into a small volume. Therefore, a heat reflective coating was incorporated between two thin,
transparent layers of LDPE on the interior. A metallized film can properly adhere to polymers.
Several metals may be used for a heat-reflective coating, including nickel, aluminum, and
chromium [11-13]
However, aluminum was chosen due to its price and lack of health risks when in contact
with skin [14]. An inner layer of LDPE keeps the metallized film out of contact with the skin, and
a metal with no major health risks is chosen in case the LDPE sheet is abraded. The inner layer
also protects the user if the metal loses adhesion with the polymer matrix [11].
Final Product Description
The user needs heavily influenced the final architecture of ThermArk. The design is a
multi-layer composition that can be used as either a blanket, or be folded into a sleeping bag. The
final architecture has the layer adjacent to the user as extruded LDPE with a thickness of 0.001
in., with those divided into two 0.0005 in. thick sheets where one is aluminized. The aluminized
sheet is separated from the user by the inmost layer of thin, transparent LDPE. The aluminized
sections are 5x5in with a 1 in. gap between each square with a thickness of 0.00064 in. The inner
foam layer is extruded LDPE foam with a thickness of 0.25 in. The layer in contact with the
environment is extruded LDPE with a thickness of 0.0025 in. and dark gray color. A total of 14
snaps, composed of injection molded PVC, provides a durable yet cost-effective sealing method.
The sides are 13 in. apart from each other, and the top and bottom are 22 in. apart.
The design can be envisioned through the CAD rendering in Figure 7. The user needs
from Figure 2 heavily influenced the material chosen for the product, and the industrial design
considerations and rankings are shown in Appendix C2. The materials utilized in the ThermArk
had to fulfill all the needs, while concurrently and effectively being thermally insulating and
affordable. Due to this hurdle, it was decided to use cost-effective and commonly recycled
materials such as LDPE and PVC. It was determined through research and analysis that the
number of components in the product can define if the product will be affordable, especially
when concerning the market. As seen on Figure 10, the lack of a viewing window deviates from
the original final concept design. The removal of the viewing window was decided due to an
increased amount of parts and complexity. This leads to an increase in material cost,
manufacturing costs, points of failure, and carbon footprint.
18. 18
Figure 10: CAD rendering of the ThermArk Thermal Insulator
Comparison to the Current Market
In comparison to what is currently on the market, ThermArk is different in many ways.
First, it is produced with materials that have a high thermal conductivity, but are cost-
effective compared to commonly used insulation in the competition. Secondly, the design allows
it to be used as either a blanket or a sleeping bag/tent hybrid. The snaps and material allows the
user to choose how they want to use the ThermArk, and are not restricted to one
configuration. The third benefit was the material and the design. The product is
very lightweight and easy to pack when not in use. LDPE was used along
with aluminized squares to provide insulation while allowing the product to maintain portability.
Compared to sleeping bags, tents, and blankets, this is less bulky and lighter weight. Lastly,
compared to our competitors, ThermArk can be downcycled and the LDPE used again in another
product. This is not always true for blankets, certain tent materials, and commonly used sleeping
bag materials.
Manufacturing Process
Materials selection included consideration for manufacturing, which excluded materials
such as woven jute for its unreliable bonding with waterproof layers. Hot bar welding can be used
for thermoplastic polymers such as LDPE, and it works by pressing the materials to be welded
between two electrically heated bars. Figure 11 shows a configuration which can weld together
layers of insulating composite. Two benefits arise from using hot bar welds to create a grid of
bonded layers: metallized sections can be included between the grid lines, and un-welded sections
can stretch to make additional, insulating air pockets. Prior to welding layers together, LDPE can
be extruded into solid and foam sheets.
19. 19
Figure 11: Hot bar welding schematic [18].
Metallizing the intermediate LDPE layer is done by physical vapor deposition. This
requires the metal to become atomized and travel through vacuum to the substrate to create a
reflective coating on that substrate [15]. At first, this process was avoided since using vacuum was
considered too expensive, but following research and discussion revealed that there are existing
cheap products which use this method. Metallizing the single LDPE layer is done after cooling
from extrusion and before stacking layers for hot bar welding.
One possible manufacturing supply chain arranges extrusion of each layer vertically, with
the thin LDPE layers at the bottom of a manufacturing tower. This allows extra equipment for
metallizing an LDPE layer to be located at a minimal height from the ground. These layers will
continue in a straight line and meet before hot bar welding is done, and the snaps will be riveted
on after cooling from hot bar welding. Individual blankets can be cut apart and folded when all
steps are finished. Quality assessment can be done using the finished product, as functional layers
can be separated where not welded. Figure 12 summarizes manufacturing and materials cost as a
Bill of Materials.
Figure 12: Bill of Materials for ThermArk
Purchasedmaterials
(AverageUSD/item)Processing
(Machine+Labor)Assembly(labor)TotalUnitvariablecostToolingandNREsToolinglifetime(yr)
Totalunitfixedcost(per
year)
Totalcost
6.05x + 2104 (USD/yr)
PVC Snaps 0.0429 0.0167 0.0444 0.1040 3770 5 754
Outer, Inner LDPE shells 0.7087 0.0167 0.0056 0.7309
LDPE foam 4.7695 0.0167 0.0056 4.7917
Aluminum heat reflector 0.2555 0.1667 0.0056 0.4277 1000 3 350
Total 6.0543 2104 x = # units per yearLabor set at $20 per hour
6.05x + 2104 (USD/yr)3000 3 1000
20. 20
Sustainability Assessment
A major consideration in the 21st
century is environmental impact of producing industrial
and consumer products. Resources such as CES EduPack 2016 list carbon footprint by mass of
material produced, allowing the pounds of carbon dioxide produced with a new product to be
estimated. ThermArk, which weighs approximately five pounds, will contribute 20.1 – 23.4
pounds of carbon dioxide for each unit produced. For scale, one jacket currently produced as a
consumer product contributes 66 pounds for each unit [16], and a gallon of dairy milk creates about
7.2 pounds of carbon dioxide. Additional considerations into sustainability are listed in Appendix
C3. Including all considerations, mass production of the product is not expected to create a
significant detriment to natural resources and environment.
Feasibility Assessment
Final metrics for the product along with the ideal and acceptable values are shown in
Appendix C4. Values which could not be exactly computed are estimated based on research into
similar products, and any assumptions made to reach the final metrics are listed.
The product specifications fall within ideal and acceptable ranges for all properties except
the metric corresponding to most important user need: thermally insulating. This results from the
need to satisfy other needs, especiallyaffordability and portability. Building a shelter to completely
insulate a rough sleeper requires far more energy than is available in producing and using the
product. Despite providing incomplete insulation, the product has waterproofing and heat-
reflective capabilities which improve the product from simple blankets used by homeless. The
primary condition of market feasibility for this product is that it satisfies the need to keep a user
alive in winter months. Satisfaction of that need requires that the user has other systems which
help insulation, such as warm clothing and some air between the user and the product. The user
may use a simple blanket with the product, further increasing his or her warmth.
Economy of scale aids financial feasibility, where production of 500,000 units per year
allows each unit a retail cost of $15. However, this price is steep for a product which is intended
to be purchased on a large scale by relief agencies. One option to relieve this problem is to sell
ThermArk to our secondary market for $30 and advertise that each blanket bought sends a blanket
to relief services.
21. 21
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23. 23
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25. 25
Appendix
Appendix A: Prioritization Matrices
Figures A1-5 contain prioritization matrices for all user needs within each supergroup
with more than one associated need.
Figure A1: Prioritization matrix for the functionality ITY
Figure A2: Prioritization matrix for the usability ITY
Figure A3: Prioritization matrix for the durability ITY
Figure A4: Prioritization matrix for the safety ITY
Figure A5: Prioritization matrix for the portability ITY
Thermallyinsulating Wind-proof/resistant Waterproof Thermalprotectionfromground Noriskofsuffocation Sum Normalized(%)
Thermallyinsulating 5 5 1 1 12 33.33%
Wind-proof/resistant 0.2 0.2 1 0.2 1.6 4.44%
Waterproof 0.2 5 1 0.2 6.4 17.78%
Thermalprotectionfromground 1 1 1 1 4 11.11%
Noriskofsuffocation 1 5 5 1 12 33.33%
Breathable Expandable Comfortable Spatially efficient Sum Normalized (%)
Breathable 5 5 5 15 45.59%
Expandable 0.2 5 1 6.2 18.84%
Comfortable 0.2 0.2 0.1 0.5 1.52%
Spatially efficient 0.2 1 10 11.2 34.04%
Enduresone monthofuse Gouge-resistant Retainsfunctionalitywhenabraded Canbe cleaned Sum Normalized(%)
Enduresone monthofuse 5 1 1 7 32.41%
Gouge-resistant 0.2 0.2 1 1.4 6.48%
Retainsfunctionalitywhenabraded 1 5 0.2 6.2 28.70%
Canbe cleaned 1 1 5 7 32.41%
Condensationcanescape Discrete Cansee surroundingsfrominside Meetslocal restrictions Lockingmechanism Antimicrobial Sum Normalized(%)
Condensationcanescape 0.1 0.1 1 5 0.2 6.4 8.53%
Discrete 10 1 5 5 1 22 29.33%
Cansee surroundingsfrominside 10 1 5 5 0.2 21.2 28.27%
Meetslocal restrictions 1 0.2 0.2 1 0.2 2.6 3.47%
Lockingmechanism 0.2 0.2 0.2 1 0.2 1.8 2.40%
Antimicrobial 5 1 5 5 5 21 28.00%
Convenient to carry Packable Simple packing Carry in mass transit systems Lightweight Sum Normalized (%)
Convenient to carry 1 0.2 10 0.2 11.4 19.96%
Packable 1 1 5 5 12 21.02%
Simple packing 5 1 10 1 17 29.77%
Carry in mass transit systems 0.1 0.2 0.1 0.1 0.5 0.88%
Lightweight 5 0.2 1 10 16.2 28.37%
26. 26
Appendix B: Concept Selection Matrices
Figures B1-3 contain selection matrices for product architecture, insulation, and accessories.
Figure B1: Concept selection matrix for the structure sub-group
Figure B2: Concept selection matrix for the insulation sub-group
Figure B3: Concept selection matrix for the closing mechanism sub-group
Appendix C: Detailed Design and Project Architecture
Appendix C1: Material Selection
Figures C1.1 – C1.5 show the decision matrices for bottom, outer layer, inner layer, foam, and
accessory materials, respectively. Not all best materials based on ratings were used because the
design assumption was to use one material to satisfy all needs.
27. 27
Figure C1.1: Materials selection matrix for layer between user and ground
(Ensolite) PVC/NBR Elastomer Woven Jute with Natural Rubber Neoprene
Price (USD/lb.) 1.85-2.10 0.159-0.68/0.862-1.09 2.4-2.8
Density (lb./in^3) 0.0397-0.0452 0.047-0.0542/0.336-0.035 0.0488-0.0542
Yield strength (ksi) 1-2.47 21-76.9/3.04-4.06 1.52-3.09
Fatigue strength at 10^7 cycles 0.4-0.986 23.2-49.9/1.22-1.62 0.661-1.24
Flexural Strength (ksi) 2.31-4.48 NR/5.34-6.85 3.27-5.41
Tear Strength (lbf/in) 143-240 NR/142-251 154-320
Tg (deg F) -9.4 - - 0.4 716-734/-108- - 81.4 -54.4- - 36.4
Thermal conductivity (BTU.ft/hr.*ft^2*F) 0.0867-0982 0.144-0.202/0.0751-0.0924 0.116-0.52
Water absorption at 24 hr. (%) 0.05-0.3 2.2-2.6/0.01-0.02 0.6-0.8
O2 Permeability (cc.mil/day*(100in^2)*atm) 61-254 NR/2.5e3-4.17e3 55-172
Water vapor transmission (g*mm/m^2*day) NR NR/11-21 NR
Chemical resistance Acceptable Limited on own/ Excellent together Excellent
Carbon footprint (lb./lb.) 3.18-3.5 2.69-2.96/1.86-2.05 2.08-2.29
Other
Excellent to extrude, not
recycled often, can be burned
for energy recovery, Issue with
Tg
Jute on its own is very biodegradable,
can weave/ extrudable but not
biodegradable; Together they are able
to be burned for energy recovery. Need
antioxidant
Extrudable, Not
recyclable and mainly
goes to landfill. Can be
burned for energy
recovery. (w/Carbon
Black)
Source CES EDUPACK 2016 CES EDUPACK 2016 CES EDUPACK 2016
Functionality 4 4 3
Affordability 4 5 3
Durability 4 5 4
Safety 3 4 4
Portability 3 3 3
Reliability 3 4 3
Usability 4 4 4
Weighted sum 348.12 402.92 315.67
LDPE Foam HDPE Foam PET Foam Cork
1.18-1.31 1.25-1.38 4.65-5.11 1.22-6.08
0.00246-0.0026 0.00361-0.00415 0.0113-0.0118 0.00578-0.0867
0.00406-0.00508 0.087-0.102 0.307-0.372 0.0435-0.104
0.0725-0.087 0.319-0.363 NR 0.0435-0.087
0.00406-0.00508 0.087-0.102 0.307-0.372 0.0725-0.174
NR NR NR NR
-193- -130 -193- -130 140-183 171-216
0.0289-0.03 0.0416-0.0451 0.0229-0.0253 0.0202-0.0243
0.4-0.5 0.5-0.7 0.14-0.18 NR
NR NR NR NR
NR NR NR NR
Acceptable Acceptable Acceptable Acceptable
4.86-5.36 4.5-4.96 7.27-8.01 0.192-0.211
Extrudable, not very
recyclable (~8-9% recycled),
can be burned for energy
recovery; Considered
adding aluminized surface
Extrudable, not very recyclable
(~8-9% recycled), can be burned
for energy recovery; Considered
adding aluminized/metalized
surface
Huge Carbon Footprint is a
negative. Can burn for energy
recovery. 20-22% of supply is
recycled. Metalize the
surface?
Biodegrades and can have
wide range of densities and
properties. Naturally
occurring. May not "roll-up"
or fold well with multiple
uses.
CES EDUPACK 2016 CES EDUPACK 2016 CES EDUPACK 2016 CES EDUPACK 2016
5 4 5 5
4 4 2 3
2 3 3 3
3 3 2 5
5 5 4 4
5 5 2 2
4 4 4 3
371.7 363.19 308.57 378.09
28. 28
Figure C1.2: Materials selection matrix for layer in contact with outside environment
Figure C1.3: Materials selection matrix for layer in contact with user
PA12 (flexible) PA12/E-glass
Polyester (cast,
flexible) PET (unfilled)
PVC (flexible,
shore A60)
PE-LD (molding and
extrusion)
Price (USD/lb.) 4.72-5.67 3.84-4.16 1.84-1.89 0.658-0.803 1.12-1.33 0.903-1.1
Density (lb./in^3) 0.0372-0.0376 0.0614-0.065 0.03650.0434 0.0466-0.0502 0.0444-0.0448 0.0331-0.0337
Yield strength (ksi) 3.19-3.63 52.2-58 1.16-2.4 7.25-7.98 1.45-1.6 1.3-2.1
Fatigue strength at 10^7 cycles 2.32 31.3-34.8 0.87-1.2 2.8-4.2 1.09-1.2 0.77-1.53
Tg (deg F) ~100 C 120 F 302 F 140 -9.4-8.6 F -193-(-130)
Thermal conductivity (BTU.ft/hr.*ft^2*F) 0.126--0.177 0.374-0.464 0.0892-0.0928 0.0797-0.0872 0.0924-0.116 0.186-0.201
Water absorption at 24 hr. (%) 20.00% 0.35-0.424% 0.5-2.5% 0.14-0.18 0.5-0.52 0.005-0.01%
Water vapor transmission 0.28 NR NR 0.464-0.707 NR 0.248-0.506
Chemical resistance Acceptable Acceptable Acceptable Highly flammable Acceptable Highly flammable
Carbon footprint (lb./lb.) 7.25-7.99 6.22-6.86 2.41-2.66 4.28-4.72 2.24-2.47 2.86-3.15
Other
Recyclable;
cannot
biodegrade;
(flexible)
Not recyclable or
biodegradable; (E-
glass fiber, woven
fabric laminate,
biaxial lay-up)
Not recyclable or
biodegradable;
(cast, flexible)
Recyclable; cannot
biodegrade;
(unfilled,
amorphous)
Recyclable;
cannot
biodegrade;
(flexible, Shore
A60)
Recyclable; cannot
biodegrade.
Processable by hot
welding.
Source CES Edupack CES Edupack CES Edupack CES Edupack CES Edupack CES Edupack
Functionality 1 3 4 5 4 5
Affordability 1 2 4 5 4 5
Durability 3 5 1 2 1 1
Safety 3 3 4 2 5 3
Portability 5 2 5 4 4 5
Reliability 2 2 2 2 2 4
Usability 3 3 3 4 3 3
Weighted sum 229.48 286.41 357.69 375.6 357.87 400.78
PET PET Alumina Foam
Zirconia Mullite
Alumina Foam
Aluminum-
polyethylene sandwich
Price (USD/lb) 0.658-0.803 0.658-0.803 15.1-22.6 9.41-11.3 9.54-12.2
Density (lb/in^3) 0.0466-0.0502 0.0495-0.0506 0.0235-0.0303 0.0206-0.246 0.0496-0.0507
Yield strength (ksi) 7.25-7.98 9.43-10.2 0.131-0.319 0.116-0.261 7.25-10.2
Fatigue strength at 10^7 cycles 2.8-4.2 2.8-4.2 0.155-0.171 0.132-0.146 4.35-5.8
Flexural Strength (ksi) 7.25-8.7 10.2-10.9 0.145-0.421 0.167-0.261 24.7-26.1
Tg (deg F) 140-183 154-176 478-496
Thermal conductivity (BTU.ft/hr*ft^2*F) 0.0797-0.0872 0.0797-0.0872 0.289-0.385 0.192-0.289 0.31-0.335
Water absorption at 24 hr (%) 0.14-0.18 0.1-0.2 0.5-1 0.5-1
Chemical resistance Acceptable Acceptable Excellent Excellent Excellent
Carbon footprint (lb/lb) 4.28-4.72 4.28-4.72 6.33-6.99 4.62-5.1 7.46-8.23
Other
(unfilled,
amorphous)
Crystalline (nucleated)
PET is more heat resistant
than the amorphous
grades, but is not
transparent. Unfilled PET
is problemtatic to
injection molded
compared to unfilled PBT;
(unfilled, semi-crystalline)
(99.5%)(0.745) 0.63
Source CES Edu Pack CES Edu Pack CES Edu Pack CES Edu Pack CES Edu Pack
Functionality 5 5 2 3 4
Affordability 5 5 1 2 2
Durability 2 2 2 2 5
Safety 2 2 4 4 3
Portability 4 4 4 3 2
Reliablilty 4 4 4 4 3
Usability N/A N/A N/A N/A N/A
Weighted sum 383.4 383.4 246.68 279.31 313.54
29. 29
Figure C1.4: Materials selection matrix for foam insulation
Figure C1.5: Materials selection matrix for snap fasteners
Polyurethane Foam Polyimide Foam (Solimide) LD Polyethylene Foam PET Foam (Armacell ArmaFORM)
Price (USD/lb.) 3.46-3.81 10-75 1.18-1.31 4.65-5.11
Density (lb./in^3) 0.00271-0.00307 0.000231 0.00246-0.0026 0.0113-0.0118
Yield strength (ksi) 0.00363-0.00435 N/A 0.00406-0.00508 0.307-0.372
Fatigue strength at 10^7 cycles 0.0127-0.0152 N/A 0.0725-0.087 N/A
Flexural Strength (ksi) 0.00363- 0.00435 N/A 0.00406-0.00508 0.307-0.372
Tg (deg F) -27.4- - 9.4 N/A -193- -130 140-183
Thermal conductivity (BTU.ft/hr.*ft^2*F) 0.0139-.0162 0.043 0.0289-0.03 0.0229-0.0253
Water absorption at 24 hr. (%) 8-10% N/A 0.4-0.5 0.14-0.18
O2 Permeability (cc.mil/day*(100in^2)*atm) NR N/A N/A N/A
Water vapor transmission (g*mm/m^2*day) NR N/A N/A N/A
Chemical resistance Below Average to Acceptable Limited use to Acceptable Acceptable Acceptable
Carbon footprint (lb./lb.) 4.95-5.46 No 4.86-5.36 7.27-8.01
Noise reduction Coefficient Unknown 0.75 N/A N/A
Other
Water absorption is high. Can
be extruded and molded.
Recycling is limited but can be
burned. Can be
downcycled! High water
absorption would increase
thermal conductivity and
weight over time
So good that NASA uses it;
single source since
proprietary things; seems
aimed at big industry =
very expensive; was not
able to find the foam on
CES EDUPack. PI is
extremely expensive and
out of our price range
Extrudable, not very
recyclable (~8-9%
recycled), can be burned
for energy recovery; Can
be downcycled!
Huge Carbon Footprint is a
negative. Can burn for energy
recovery. 20-22% of supply is
recycled. Can be downcycled as
well.
Source CES EDUPACK 2016 CES EDUPACK 2016 CES EDUPACK 2016
Functionality 2 3 4 4
Affordability 4 1 5 3
Durability 3 1 3 4
Safety 2 2 4 3
Portability 4 5 4 3
Reliability 3 1 5 3
Usability 3 4 3 3
Weighted sum 2.9988 2.2646 4.132 3.3943
Snaps Brass ABS PVC (rigid molding) PLA PP POM
Price (USD/lb.) 2.72-2.99 1.13-1.36 0.762-0.93 1.27-1.55 1-1.1 1.53-1.66
Density (lb./in^3) 0.308-0.314 0.0376-0.0387 0.047-0.0538 0.0448-0.0456 0.0325-0.0328 0.0509-0.517
Yield strength (ksi) 17.4-20.3 6.09-6.67 6-7.64 7.98-10.4 4.77-5.28 9.5-10
Fatigue strength at 10^7 cycles 21.8-22.6 2.04-2.65 2.4-3.06 3.22-4.02 2.13-2.24 3.46-4.49
Fracture Toughness( Ksi/in) 59.6-64.1 1.73-1.91 3.3-3.5 3.04-4.36 1.92-2.02 3.46-3.82
Tg (deg F) NR 212-230 176-190 126-140 6.8-21.2 -76 - -58
Chemical resistance Excellent Acceptable Excellent Acceptable Excellent Acceptable
Carbon footprint (lb./lb.) 0.973-1.08 1.17-1.29 0.947-1.05 0.9-0.995 1.06-1.17 1.67-1.84
Other
CuSn20; Can be
plated; recyclable,
press forming but
not castable
Excellent choice
for ease of
manufacture (can
mold, extrude, and
thermoform); can
recycle or burn for
energy recovery
Injection
Moldable; can
recycle or burn for
energy recovery
Acceptable choice for
manufacturing (can
mold, extrude, and
thermoform); Excelle
nt for recycling; can
biodegrade
Excellent choice
for ease of
manufacture (can
mold extrude, and
thermoform); Can
recycle and can
burn for energy
recovery
Injection
Moldable; can
recycle or burn for
energy recovery
Source CES EDUPACK 2016 CES EDUPACK 2016 CES EDUPACK 2016 CES EDUPACK 2016 CES EDUPACK 2016 CES EDUPACK 2016
Functionality 4 3 3 4 2 3
Affordability 1 3 5 2 4 5
Durability 5 3 3 4 3 3
Safety 4 2 4 3 3 1
Portability 2 5 4 4 5 3
Reliability N/A N/A N/A N/A N/A N/A
Usability N/A N/A N/A N/A N/A N/A
Weighted sum 289.07 297.04 360.53 312.65 312.47 298.99
30. 30
Appendix C2: ID Charts
Figure C2.1 shows industrial design basis for the final product architecture.
Figure C2.1: Industrial design chart
Quality of User
Interface
Emotional Appeal
Ability to Maintain
and Repair the
Appropriate Use of
Resources
Product
Differentiation
Numeric rating
Performance
rating Explanation of score
Quality of User
Interface
7
Interface allows user to get functionality with or without knowing how to use the snaps
on the side
Emotional Appeal 2
Emotional appeal comes from helping the user survive, but product is designed to avoid
prolonging users' homeless condition
Ability to Maintain
and Repair the
Product
4
Primarily made of materials which can be effectively washed with water. Stretched LDPE
cannot be returned to its unstretched state
Appropriate Use of
Resources
10
No excess material is used on this product, with the exception that the user chooses to
not use the snaps
Product
Differentiation
6
Product is very much like a blanket, but is set apart by waterproofing and cushioning
from the ground.
0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%
Quality of User Interface
Emotional Appeal
Ability to Maintain and Repair the Product
Appropriate Use of Resources
Product Differentiation
Percent importance
Performance Rating
31. 31
Appendix C3: Sustainability
Figure C3.1 shows considerations for designing a sustainable product and what factors of the
product qualify for or against sustainability.
Figure C3.1: Design for sustainability matrix
Appendix C4: Final Ideal and Marginally Acceptable Metrics
Figure C4.1 is the matrix of final product property specifications for ideal and marginally
acceptable values. Assumptions for calculations are included. Ideal and acceptable values were
determined when metrics were defined for the needs-metrics matrix [18-40]
Additional assumptions for the thermally insulating metric were made to account for heat
reflection. The aluminized surface covers approximately 70% of the surface area, and near 100% of
heat generated by the user is expected to be reflected by aluminized sections. Energy transfer per
hour was therefore reduced by 70% of 330 BTU/hr produced by the user [17].
Product Score ThermArk
Inherent Rather Than
Circumstantial
Designers need to strive to ensure that all materials
and energy inputs and outputs are as inherently
nonhazardous as possible.
Yes
No hazardous waste produced in
manufacture, and product materials are
chosen to minimize health risk
Prevention Instead of
Treatment
It is better to prevent waste than to treat or clean up
waste after it is formed.
Yes
Process does not produce any harmful
emissions to be scrubbed
Design for Separation
Separation and purification operations should be
designed to minimize energy consumption and
materials use.
Yes Easily separated marterials used.
Maximize Efficiency
Products, processes, and systems should be
designed to maximize mass, energy, space, and time
efficiency.
Yes
Product and process designed to
maximize efficiency
Output-Pulled Versus
Input-Pushed
Products, processes, and systems should be "output
pulled" rather than "input pushed" through the use
of energy and materials. Demand-Driven Production
No
Market demand and production are
based on emergency preparation.
Conserve Complexity
Embedded entropy and complexity must be viewed
as an investment when making design choices on
recycle, reuse, or beneficial disposition.
Yes
Fabricated from one material so it can be
recycled without separation
Durability Rather Than
Immortality
Targeted durability, not immortality, should be a
design goal.
No Not biodegradeable but recyclable
Meet Need, Minimize
Excess
Design for unnecessary capacity or capability
solutions should be considered a design flaw.
Yes
No extra "bells and whistles" and is a
"one-size fits all" configuration
Minimize Material
Diversity
Material diversity in multi-component products
should be minimized to promote disassembly and
value retention.
Yes
Three materials are used: LDPE, PVC, and
aluminum
Integrate Material and
Energy Flows
Design of products, processes, and systems must
include integration and interconnectivity with
available energy and materials flows.
Yes
Product and energy move linearly
through assembly
Design for Commercial
"Afterlife"
Products, processes, and systems should be
designed for performance in a commercial
"afterlife."
Yes May be recycled
Renewable Rather
Than Depleting
Material and energy inputs should be renewable
rather than depleting.
Yes
Material can be made of recycled
material
Sustainability Measure
32. 32
Figure C4.1: Final product metrics
Metric Description Unit Final Product Ideal Values Marginally Acceptable Values Calculation Assumptions
Thermally insulating BTU/hr 1315.8-1258.9 300-400 400-700
Temperature difference is 50 degrees Fahrenheit, 70%
of heat reflected back to user. Surface area between
user and environment is estimated at 2 m² (21 ft²).
Internal Temperature ˚F 60 70 60-75
Breathable mL/hr 0.00027 0.00125 0-0.00125
Water-Resistance
% Water absorption
@ 24 hours
0.01% <1% 1-3%
Wind-breaking mph 50 35+ 35-60
Consumer Cost $ $12 <$5 $5-30 Average price with 300,000 units produced per year
Cost to Manufacture $ per unit $10 <$1 $1-15 Average price with 300,000 units produced per year
Cost of Distribution $ per unit $2 <$1 $1-12
20% of average price with 300,000 units produced per
year
Percent Recycled
Materials Used
% 0-100% 100% 50-100% Can use recycled material
Lifetime of product Days 25-40 40 25-40 Depends on use
Use Cycles until failure Discrete 90(-20) 120 90 (-20)
Material Strength Yield strength, ksi 1.3-2.1 5+ 2 +/ 3 Strength of outer LDPE sheets
Load required to open Load, kg 0-10 15 0-10 Can be increased with using snaps
Chemical Resistance Acceptability Acceptable. Excellent Acceptable Acceptability reduced because highly flammable
Visibility subjective
Gray color on outside
layer
N/A
Avoid colors such as red in high amounts of light
and yellow in low light. Shades of blue, grey,
black, and green are less visible at distances.
Ensure no reflective material is used.
User Visibility Binary Yes Yes Yes or no Limited to opening near head
Microbial Growth CFU's/ml
Can be washed to
remove bacteria
0 Washable
Legality Unitless, binary Meets Meets Meets or does not meet
Steps to set-
up/breakdown
steps 2-5 4 2-4 Depends on snap use
Time to set-
up/breakdown
minutes 1.5-8 1 "1 -14 Depends on snap use
No unused material on
product
Unitless, binary Meets Meets
The thermal blanket accomplishes its task with
minimal amounts of extra material
Extra material used as extra layers of insulation
Volume when packed ft^3 3.672 0.706 .706-3.88
Assumes foam can be elastically compressed to 1/3 of
unloaded volume
Weight lb 4.94-4.71 4.4 11 +/- 5
Follows rules for
MARTA, bus, etc.
Unitless, binary Meets Meets Meets or does not meet
Conducive to Sleep subjective
Provides some
cushioning
N/A Allows user to get 7-9 hours of sleep
Internal Relative
Humidity
% 30-60 50 30-60 Can adjust humidity by exchanging air with outside
Length ft 7 6.56 5.6-6.2
Width ft 6 2.78 2.16-2.78 Can be folded over
Height ft 6 2.25 2.25-2.165 Allowed by wrapping
Sound Dampening Db 30-50 <30 30 - 50 Used as sound dampening in buildings
