DEFINING BEST PRACTICES INDICATORS
FOR DECONSTRUCTION OF GYPSUM
BASED PRODUCTS TOWARDS AN
EFFECTIVE CLOSED-LOOP
A. DE GUZMÁN-BÁEZ, A. JIMÉNEZ-RIVERO, M. RODRÍGUEZ-QUIJANO,
J. GARCÍA-NAVARRO
Research Group Sustainability in Construction and Industry giSCI – UPM.
Technical University of Madrid. Ciudad Universitaria s/n, 28040 Madrid, Spain
SUMMARY: Whereas building demolition is synonym of destruction, resulting on what is
usually known as debris, selective demolition or deconstruction devotes special attention to
cause minimal damage on materials through on-site waste segregation, therefore increasing the
re-use or recycling options. Consequently, segregation becomes essential for effectively close
the loop of certain building materials, as for the case of gypsum waste. Aiming to define the best
practices indicators for assessing the deconstruction of gypsum based products, five pilot
projects in four European countries (Belgium, France, Germany and the United Kingdom) have
been monitored through a set of economic, environmental, social and technical parameters.
These parameters have been combined in resulting indicators that enable to assess different
aspects compared to demolition practices, such as the effectiveness of the deconstruction and
segregation processes, waste traceability, labour time, costs and the environmental impacts
targeted. The differences arising in each country have also been underlined. The study has been
conducted within the framework of the Life+ GtoG project, which from January 2013 is working
for transforming the gypsum waste market, with the aim of achieving higher gypsum recycling
rates and promoting deconstruction practices in Europe.
1. INTRODUCTION
Gypsum products are considered amongst the very few construction material whose closed-loop
recycling is possible, being increasingly into widespread used.1.15 million tonnes of plasterboard
waste were generated 2012 (Gypsum to Gypsum project, LIFE11 ENV/BE/001039, 2013). This
is predominantly plasterboard in the form of offcuts from construction sites and stripped-out
plasterboard from demolition and renovation sites (Gypsum Recycling International, 2002).
Deconstruction is identified as an effective means for reducing C&D mixed waste at a time of
diminishing landfill capacities and increasing environmental awareness (Nisbet, Venta, & Foo,
2002). However deconstruction is still perceived as more costly and its economic viability differs
considerably according to local condition (Coelho & de Brito, 2011). Government policies are
beginning to address the advantages of deconstruction by increasing or forbidding the disposal if
Proceedings Sardinia 2015, Fifteenth International Waste Management and Landfill Symposium
S. Margherita di Pula, Cagliari, Italy; 5 – 9 October 2015
 2015 by CISA Publisher, Italy
Sardinia 2015, Fifteenth International Waste Management and Landfill Symposium
the materials are useful (Saghafi & Teshnizi, 2011). Notwithstanding, techniques and tools for
dismantling the existing structures are still under development, with a limited number of studies
and researches carried out (Chini & Nguyen, 2003).
The establishment of a system of indicators has been set in recent years as a simple method of
evaluation in decision-making processes (Srinivasan, Ingwersen, Trucco, Ries, & Campbell,
2014) . The indicators give quantitative, qualitative or descriptive measures that simplify the
information available about an item and / or quality of a process, in a relatively simple way to
use and understand (García Navarro, Maestro Martínez, Huete Fuertes, & García Martínez,
2009). In this sense, the information given must be relevant and useful to ease the decisions that
will be taken on the basis of their results, in order to optimize the processes that are being
measured and identify changes and improvements (Picado, 1997).
The research conducted in this paper, in the framework of the Life+ GtoG Project ―From
Production to Recycling, a Circular Economy for the European Gypsum Industry with the
Demolition and Recycling Industry‖, exposes the methodology developed for the formulation of
a set of indicators for monitoring deconstruction practices, considered the most suitable for data
collection, analysis and evaluation of the end of life stage of gypsum base products.
These indicators are grouped into four categories: technical, economic, social and
environmental, joining the intrinsic characteristics of the deconstruction project to the triple
traditional approach of sustainability (Yuan, 2013).
Its application in a series of case studies, located in five of the eight European countries under
study within the GtoG project, Germany, Belgium, France, The Netherlands, and The UK, will
assess their suitability. Providing conclusive data on the impact due to deconstruction activities,
identifying possible areas of improvement to increase the recovery of waste capable of being
recycled, maximize quality and increase the percentage of recycled gypsum reincorporated in the
manufacturing of gypsum products.
Aiming to define the best practices indicators for assessing the deconstruction of gypsum
based products, this paper discusses the results obtained from the analysis of five case studies
part of the GtoG project, where deconstruction practices were monitored and studied. The study
addresses the need for an effective deconstruction process to optimize the plasterboard waste
recycling. This control and monitoring of waste generated is important for transparency in the
analysis of the process (Yuan, 2013).
2. METHODOLOGY
2.1 Development of the performance indicators for deconstruction
The aim of monitoring gypsum deconstruction system deconstruction practices in different pilot
projects is to set the basis for a technical, environmental and socio-economic assessment
framework, for the effectiveness of the deconstruction process. The study of the practices
implemented and the results obtained not only from the demonstration actions in the pilot project
but also from previos preparatory acctions where a thorought review on existing literature and
the gypsum business model was analysed, have led to the identification of the key influencing
parameters and resulting indicators. In addition to evaluating the deconstruction techniques
performance, these indicators also enables to monitor and compare progress, and when
appropriate, from the output data, the formulation of mitigation measures to avoid and minimize
the negative effects derived from potential weaknesess detected.
The indicators were evaluated, validated and refined within the implementation actions by their
Sardinia 2015, Fifteenth International Waste Management and Landfill Symposium
application in the pilot project, taking into account the characteristic of each case study and the
different national context.
2.1.1 Parameters
The first part of the methodology consists on selecting the parameters that will constitute the
indicators according to the impact to be measured. Such impacts were determined and obtained
from a previous study conducted within the GtoG project, in which current practices in
deconstruction demolition, C&D waste characterization, processing of the gypsum waste for the
production of recycled gypsum and its reincorporation into the manufacturing process were
analysed and evaluated. A number of drivers influencing the market share for gypsum recycling
were identified and classified into technical, economic, environmental and legislative aspects.
According to that, a first approach of the aspects to be measured was formulated and their related
significant parameters established. Table 1 shows the set of parameters selected concerning, the
data availability andcategory to be measured.
Category
Economic
Technical
Table 1. Deconstruction practices monitoring parameters
Parameter
Floor area of deconstruction site
Cost of the audit
Duration
Area of partition
Dismantling and loading cost
Transport cost, including gate fee and taxes
Cost of disposal, including all taxes
Gypsum waste foreseen
Gypsum waste generated
Recyclable gypsum waste foreseen
Recyclable gypsum waste generated
Level of presence of impurities
GW refused for non compliance with the specifications
Certified end route of GW tracked
Tracked recyclable and non recyclable GW sent to landfill
Environmental Gypsum Waste (GW) transported
Gypsum Waste (GW) received per load
Number of kilometers
Emissions of CO2 per transport unit (tonne-km)
Social
Labour time by man needed for the dismantling and loading
Labour time by man estimated to demolish and loading
Number of total hours of training received per year
Labour time by man devoted to follow-up the waste management (incl.
tracking records)
Existence and number of workers trained for the jobsite
Existence of worker(s) appointed to follow-up the waste management (incl.
tracking records)
Sardinia 2015, Fifteenth International Waste Management and Landfill Symposium
2.1.2 Indicators
Parameters were combined together to give rise to the associated key assessment indicators,
resulting on the definition of a set of 14 main indicators classified into the four main categories
to be monitored (Table 2).
Category
Economic
Table 2. Deconstruction practices monitoring indicators
Indicator
Definition
ECO 1. Audit cost
Cost of the audit per square meter of the building
project.
ECO 2. Dismantling Cost of plasterboard dismantling and loading per square
cost plasterboard
meter of plasterboard.
ECO 3. Dismantling Cost of plasterboard blocks dismantling and loading per
cost gypsum blocks square meter of gypsum blocks.
Technical
ECO 4. Cost
difference between
recycling and
landfilling routes
TEC 1. Deviation of
the audit
Cost difference per tonne between recycling and
landfilling routes, either direct or via transfer station,
including gate fee and tax.
TEC 1.1. Deviation percentage between the amount of
GW foreseen and GW generated.
TEC 1.2. Deviation percentage between the amount of
recyclable GW foreseen and recyclable GW generated.
TEC 2. Efectiveness
of the dismatling,
segregation and
storage
TEC 2.1. Existence or non existence of visual
contaminants in the GW stored before being loaded.
TEC 3. Level of
traceability
Deviation between the GW tonnage generated and the
tonnage tracked.
Environmental ENV 1. Landfill
end route
Percentage of GW that could have been recycled but has
been sent to landfill for non compliance.
Social
TEC 2.2. Deviation percentage between the recyclable
GW sent and the GW refused at the recycling facility.
ENV 2. Transport
emissions
comparison
SOC 1. Labour time
plasterboard
Transport CO2 equiv emissions from the jobsite to the
recycling facility compared with emissions from the
jobsite to landfill.
Difference between the labour time needed in minutes to
dismantle-load and demolish-load a square meter of
plasterboards.
SOC 2. Labour time
gypsum blocks
Difference between the labour time needed in minutes to
dismantle-load and demolish-load a square meter of
gypsum blocks.
SOC 3. Productivity Square meter of gypsum waste dismantled, sorted and
loaded by trained workers per day.
SOC 4. Training of
the deconstruction
team
SOC 5. Follow-up
of the waste
management
Number of hours of training in waste dismantling,
sorting and storing per number of trained workers.
Existence or non existence of a person appointed to
follow-up the waste management including the tracking
records.
Sardinia 2015, Fifteenth International Waste Management and Landfill Symposium
Table 3. Deconstruction pilot projects description. Case studies D1-D5.
General data
Country
Description
of the
building
D1
Brussels
2 floors
building, offices
Gypsum
system (m2)
Duration
(months)
Type of
gypsum
system
found
D2
France
3 floor bulding,
commertial
D3
England
12 floor
building, offices
D4
France
9 floor
building,
offices
D5
Germany
5 single-floor
buildings,
offices
2.800
340
8.640
6.750
3.450
5
2
5
6
4
Plasterboard
partition,
metallic frame,
mineral wool
insulation
Waste
fractions
D1
Recyclable
Gypsum
Waste (t)
Non-recyclable
Gypsum Waste (t)
28,00
Deconstruction
D1
description
Dismantling Mechanically
Sorting
Mechanically
Loading
Mechanically
(bobcat)
Waste
management
option
Recycling
facility
Gypsum block
partition;
Plasterboard
partition, metallic
frame;
Insultaion
system:
plasterboard,
expanded
polystyrene;
Plasterboard
ceiling, metallic
frame.
D2
9,38
Plasterboard
partition, metal
frame,
glass/rock wool
insulation.
Double
plasterboard
partition,
metallic frame,
glass wool
insulation.
D3
D4
50,00
67,52
7,80
D2
Manually
(automatic
screwdriver and
pickaxe)
Removal by hand
Manually
(wheelbarrow
and shovel)
Mechanically
(telescopic
rotating forklift)
Recycling facility
Plasterboard
ceiling,
wooden frame,
mineral wool
insulation;
Plasterboard
laminate,
metallic frame;
Plasterboard
partition,
wooden frame,
wood wool
insulation.
D5
23,64
13,00
D3
D4
D5
Manually
(crowbar,
pickaxe or
sledgehammer)
Removal by
hand
Manually
(hopper)
Manually
(automatic
screwdriver
and pickaxe)
Removal by
hand
Manually
(hopper)
Mechanically
(bobcat)
Mechanically
(bobcat)
Manually (
crowbar,
pickaxe or
sledgehammer)
Removal by
hand
Manually
(wheelbarrow
and shovel)
Manually and
mechanically
Recycling
facility via
transfer station
Recycling
facility
Recycling
facility via
transfer station
Sardinia 2015, Fifteenth International Waste Management and Landfill Symposium
2.2 Pilot projects description
The deconstruction techniques from five different construction projects were monitored in order
to compared and quantify the different category impacts in which they are divided as well as
validate their feasibility. In all cases gypsum waste was dismantled manually or mechanically,
segregated at source and transported to different recycling facilities according to the project’s
respective locations, for a posteriori processing into recycled gypsum. The pilot projects were all
tertiary buildings located in countries where deconstruction is a usual practice. Table 3 presents
the general characteristics of the five type of deconstruction works applied.
3. RESULTS
The results are intended to provide an overview of each deconstruction pilot project, to reveal
those aspects which are performing well and not so well, in order to point the way to next steps
towards the definition of best practice indicators. It is worth mentioning that the intention is not
to produce an absolute number as a performance index, but guidance criteria for evaluation that
will be the basis of further developments.
The results obtained have been analysed and are described in the subsections presented below
per type of indicator.Table 4 sets out the 14 proposed indicators, their units of measurement and
the criteria used to assess the performance of the deconstruction process.
3.1 Economic indicators
Indicator ECO1, audit cost, focuses on the price of the deconstruction audit in each context. The
average audit cost in 0.72 €/m2. A mandatory audit or previous estimation of the amount of
waste is not currently a requirement in the UK (D3); therefore the audit cost could not be
provided by the construction company (Table 4). Case studies D2 and D4, both located in
France, present the highest and lowest cost, around 2.6 and 1/10 of the average cost,
respectively.
Indicator ECO2 and ECO3, dismantling cost, show how dismantling gypsum blocks is 10
times less costly when compared to plasterboard systems, as plasterboard are screwed on a
metallic framework, which impact the dismantling time and thus the related cost. Gypsum blocks
were only generated in 1 out of the 5 case studies (D2). They may be found in France, Belgium
or Germany, whereas they are not commonly used in the UK.
Indicator ECO4, cost difference between recycling and landfill routes, shows that, only for the
case study D3, landfill is more economically favourable, as the cost of recycling via transfer
Indicator
D1
D2
Table 4. Economic Indicators results
D3
D4
D5
Unit
ECO 1
0,46
1,90
n/a
0,08
0,43
€/m2
ECO 2
0,50
2.30 0.22
5,98
2,30
2,60
€/m2
ECO 2
0,83
2,30
5,98
2,30
2,60
€/m2
No
blocks
24,59
No
blocks
-36,67
No
blocks
-
€/m2
ECO 3
ECO 4
No
blocks
-100,00
0,22
-55,00
€/t
Evaluation criteria
The nearest to 0, the
cheapest
The nearest to 0, the
cheapest
The nearest to 0, the
cheapest
The nearest to 0, the
cheapest
Negative value = savings
Sardinia 2015, Fifteenth International Waste Management and Landfill Symposium
station, 129.59 euros per tonne, is higher than the cost of landfilling, 105 euros per tonne.
3.2 Technical indicators
Indicator TEC1, deviation of the audit, shows differences higher than 10% in the quantity of GW
foreseen and generated in D1, D3 and D4, and differences higher than 20% in the quantity of
recyclable GW foreseen and generated in D1, D3, D4 and D5. Therefore, only D2 comply with
the evaluation criteria proposed. In case study D4, some partitions that were supposed to be
made of plasterboards were actually made of wood, which caused this great deviation (Table 5).
Indicator TEC2, effectiveness of the dismantling, segregation and storage, demonstrate an
effective deconstruction process in all cases, with minimum amount of impurities in the gypsum
load and zero waste rejected by the gypsum recycler. The level of traceability, measured by
TEC3, is also exemplary, as the 100% of the gypsum waste generated has been properly tracked
by the waste owners.
3.3 Environmental indicators
Environmental impact is evaluated against two indicators. ENV1, landfill end route, shows that
45.5% of the gypsum waste generated in D2, and 55% of the gypsum waste generated in D5,
were sent to landfill, which correspond to non-recyclable gypsum waste, which is waste that
does not comply with the Waste Acceptance Criteria of the gypsum recycler. On the other hand,
in 3 of the 5 case studies lower transport emissions are generated when following the recycling
route (Table 6).
3.4 Social indicators
In Table 7, SOC1 shows how, in general, dismantling and loading plasterboard requires higher
labour time than demolishing and loading. SOC2 is only applicable to D2, which highlight
important time saved when dismantling this type of gypsum waste.
Table 5. Technical Indicators results
* When presence of impurities or TEC2.2<95% it is considered "Low effectiveness".
Indicator
TEC 1
TEC 1.1
TEC 1.2
D1
Nonaccept
0,28
0,28
D2
D3
D4
D5
-0,06
-0,14
Nonaccept
0,29
0,29
Nonaccept
0,80
0,71
Nonaccept
0,08
0,41
Accept
Unit
Evaluation
criteria
Acceptable if:
%
%
TEC 2
High
effective
High
effective
High
effective
High
effective
High
effective
TEC 2.1
N
N
N
N
N
Y/N
TEC 2.2
100
100
100
100
100
%
TEC 3
100
100
100
100
100
%
TEC1.1< 0.1
TEC1.2< 0.2
High
effectiveness if:*
No presence of
impurities (N)
TEC2.2 > 95%.
Must be the
nearest to 100%.
Sardinia 2015, Fifteenth International Waste Management and Landfill Symposium
Table 6. Environmental Indicators results
**In D5 case study, assumption taken from WRAP Report (WRAP, 2008). ***In D5 case study,
assumption taken from DA1 Report (GtoG, LIFE11 ENV/BE/001039, 2013)
Indicator
D1
D2
D3
D4
D5
Unit
ENV 1
0,00
45,40
0,00
0,00
0,55
%
ENV 2
-385,53
-46,34
-915,04
225,79
95,74
kg CO2
equiv
ENV 2.1
6,08
24,95
34,96
441,31
269,50
ENV 2.2
391,61
71,29
950,00
215,52
173,75
Evaluation
criteria
Must be the
nearest to 0%.
Negative
value =
savings
kg CO2
equiv
kg CO2
equiv
-
Table 7. Social Indicators results
Indicator
D1
D2
D3
D4
D5
Evaluation
criteria
A negative
min/m2 result indicates
time saving
A negative
min/m2 result indicates
time saving
A high value
m2 /
indicates
(worker
greater
*day)
productivity
Unit
SOC1
0,00
1,00
0,00
-0,13
0,00
SOC2
No
blocks
-3,50
No
blocks
No
blocks
No
blocks
SOC3
0,65
0,71
7,83
3,75
4,88
SOC4
0,53
1,67
1,50
0,47
10,00
hours/w
orkers
-
SOC5
Yes
Yes
Yes
Yes
Yes
Yes/No
-
SOC3 results not representative of the case studies, as the duration of the deconstruction
works are not exclusively taking into account the gypsum waste dismantling processeses, but all
deconstruction activities. Therefore, a time factor would be required for the accurate calculation
of this value.
In all case studies, a worker has been appointed to follow-up waste management activities
(SOC5), and hours of training in waste dismantling, sorting and storing, ranged from around 0.5
to 10, are received by trained workers.
4. CONCLUSIONS
This paper aims to define an assement framework for plasterboard deconstruction practices by
defining a set of performance indicator which has been implemented in five pilot projects to
anaylise, compare and validate the effectiviness of the same. The most relevant conclusions are
outlined below.
Sardinia 2015, Fifteenth International Waste Management and Landfill Symposium
A set of 14 key indicators classified into the four main impact categories (technical, social
economic and environmental), was developed to monitor deconstruction practices.
Auditing is not a practice implemented in all pilot projects. The deviation of the audit shows
differences higher than 20% in 4 out of the 5 of the case studies. In order to minimize the
observed deviation, detailed information about the quantity, quality and recyclability of the
gypsum based products, including results from destructive test when needed, should be part of
the deconstruction audit report.
Gypsum blocks were found only in one pilot project. Their dismantling is 10 times less costly
when compared to plasterboard systems.
Recycling is the most economically favorable route in almost all the pilot projects but for the
case of UK, as cost of the recycling via transfer station is higher than landfilling.
The dismantling, segregation and storage, is shown to be effective in all cases, with minimum
amount of impurities in the gypsum load and zero waste rejected at the recycling facility.
In 3 of the 5 case studies lower transport emissions are generated when following the
recycling route.
Dismantling and loading of plasterboard waste requires higher labour time than demolishing
and loading it.
Results evidence the feasibility of implementing deconstruction techniques instead of appling
demolition practices for gypsum products. Therefore, priority ought to be given to efforts to
promote dismantling of gypsum systems.
AKNOWLEDGEMENTS
This study has been performed under the framework of the GtoG project, supported by the
European Commission – DG Environment through the Life + programme; under contract number
LIFE11 ENV/BE/001039.
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