A Perda Máxima Provável (PML) é a estimativa da perda máxima que poderia ser suportada pelas seguradoras como resultado da ocorrência de um cenário de risco considerado pelo subscritor dentro dos domínios da probabilidade. Construções industriais são empreendimentos únicos, significando que não há muitos dados de falhas ou eventos anteriores semelhantes servindo de referência, e dinâmicos, porque a configuração local muda à medida que o progresso físico da construção avança. Neste contexto, a estimativa PML, antes da construção, é difícil, por exemplo devido à imprecisão da estimativa de custo dos danos como % do custo de construção, uma vez que o próprio custo de construir algo pela primeira vez é, por sua vez, uma estimativa imprecisa. Além disso, as ações necessárias para reparar o dano às vezes podem não ter nenhuma semelhança com o trabalho necessário para construir o ativo danificado e, portanto, não integra a estimativa de investimento para construção. As condições que irão operar para criar o evento que produzirá a perda do cenário PML não são evidentes na fase de subscrição, ou mesmo quando da realização de vistorias de Engenharia de Risco, não sendo passíveis de avaliação apenas por inspeção direta ao longo da construção. Este trabalho apresenta um método quantitativo e baseado na opinião de especialistas, para avaliação do PML em construções. Nele, a análise de consequências avalia a extensão dos danos com base em fatores objetivos como altura do ativo, materiais temporários e definitivos envolvidos na construção, conformidade com normas de segurança, entre outros.

1. BRG | Construction
Probable Maximum Loss Evaluation

2. Probable Maximum Loss (PML)
What is:
An estimate of the maximum loss which could be sustained by the insurers as a result of
any one occurrence considered by the underwriter to be within the realms of probability.
Objective:
To support the decision about how much of a risk they the underwriters can retain, and whether they need to
purchase reinsurance for their share of that risk.
When applied:
For construction projects, PML assessments are normally made for four covers provided:
• Contractors All Risks cover
• Existing Structures cover
• Non-Negligent Damage cover
• Advance Loss of Profits cover

3. BRG´s PML structured evaluation
process
The method is quantitative and BRG uses a structured PML evaluation process based on expert opinion.
This method is employed because BRG´s experts know that constructs have unique, where historical data is not
always available, and dynamic, because the configuration of the site changes as the physical progress of the
construction changes, conditions in case of accidents occur:
• The nature and extent of damage is often difficult to predict:
No examples of previous, similar failures or events to use as a
guide
• The cost of repairing damage is often difficult to predict:
o The cost of building something for the first time is an
estimate.
o The actions required to rectify damage can sometimes
bear no similarity to the work that was done to build the
thing that has been damaged. This makes estimating
costs even more difficult.
• The conditions that will operate to create the event that will
produce the PML scenario loss are not evident at the
underwriting stage, or even when Risk Engineering surveys are
carried out, and so are not capable of evaluation by direct
inspection.
Source: AACE - Recommended Practice No. 18R-97

4. BRG´s PML structured evaluation
process
Information
Collection
• Geographical situation
• Map
• Plot Plan and project areas´ layouts
• Construction Plan
• Commissioning Plan
• Schedule
• Contracting packages
• Construction utilities, storage, etc.
• Traffic data
• Climate data
• Specs
• Physical and Chemical data of construction materials, feeds, fuel, etc.
Target Risks and
PML Scenarios
specification
Base-value at risk
definition
Consequence
analysis

5. BRG´s PML structured evaluation
process
Information
Collection
Target Risk is most easily defined as that part of the insured property that is
judged to be at risk of damage in the loss scenario being considered.
Constructions have a number of characteristics that should be considered
in the definition of the target risk:
• Scaffolding on the outside face of buildings
• Temporary buildings placed between buildings being worked on
• Storage of combustible materials, combustible waste, plant, fuel/oil, gas
bottles etc. in the gaps between buildings
• Combustible materials incorporated in fixtures and fittings installed during
erection stage
• Buildings with high inherent fire loads – e.g. timber-framed buildings
• Existence of common basements beneath groups of buildings, etc.
Target Risks and
PML Scenarios
specification
Base-value at risk
definition
Consequence
analysis
Input: Collected information, BRG´s construction expert judgment
Output: Target Risks Register, Set of PML Scenarios
Examples:
• Belt fire in belt conveyor hot commissioning tests
• Fire welding in the final erection of the mill building´s metallic structure

6. BRG´s PML structured evaluation
process
Information
Collection
Analysis of the cost of construction for the areas and structures involved in
the set of specified PML scenarios.
BRG's construction experts have the experience and knowledge to
identify the plots that are or are not subject to the target risk specified,
considering only the construction cost of the affected plots and consider cost
estimates related to damages recovery actions for the Target Risk specified.
The experts also consider the possibility of the construction costs growth
for each area involved in the PML scenario specified as a function of the
precision associated with the estimation method and the advance of the
engineering project.
Target Risks and
PML Scenarios
specification
Base-value at risk
definition
Consequence
analysis
Input: Project´s Cost Breakdown Structure (CBS), costed Bill of Quantities
Output: Base-value cost of the Target Risk = Largest possible loss that can
be incurred from the Target Risk

7. BRG´s PML structured evaluation
process
Information
Collection
Assessment of the likely extent of damage (% of base-value) for the Target
Risk and PML Scenario specified
Given the PML scenario, the BRG´s estimate of extent of damage uses factors
that consider:
• Proximity and isolation between adjacent constructions
• Height of buildings
• Materials involved
• Contractor´s H&S practices and site control: compliance with regulations and
procedures, material storage, electrical installations, etc.
• Level of passive fire protection
• Structure and response of the fire brigade and fire-fighting water supplies
• Etc.
Target Risks and
PML Scenarios
specification
Base-value at risk
definition
Consequence
analysis
Input: Target Risks Register, Set of PML Scenarios, Base-value cost of the
Target Risk
Assessment Output: Material damage PML = Base-value cost adjusted
downwards to become the largest probable loss for the Target Risk
Final PML = Material damage PML, which Underwriters then amend by adding
other costs (debris removal, inflation, price escalation, etc.), as determined by
the applicable insurance policy.

8. Contact information
cgraeff@thinkbrg.com
+55 11 94550-3892
www.thinkbrg.com
www.linkedin.com/company/berkeley-research-group-llc
Berkeley Research Group
THINK TANK