1

Risk Assessment using Scoring System Methodology (SSM) as holistic substitute for IBC Height & Area Table

Frank Noonan

Professor of Industrial Engineering & Fire Protection Engineering

Worcester Polytechnic Institute

For AFSCC, 8/3/07, Chicago, Il.

2

The challenge H&A Table overly prescriptive? Incomplete with respect to assessing all

relevant factors that make a given building size safe or unsafe.

Goals: Holistic approach. Acceptable level of fire safety for communities,

occupants, emergency responders.

3

Scoring System Methodology Widely used throughout global economy for risk

assessment. Pioneered by banking industry to assess likelihood

for default with loan applications. Other applications:

IRS audit decisions Parole board decisions Mass mail and telemarketing decisions Insurance industry customer screening Hospital patient procedure decisions

4

Scoring Model Example

Risk Index Explanatory Level Factors& Data

Very Poor RiskPoor RiskMedium RiskRelatively Good RiskGood RiskVery Good Risk

-Personnel Experience-Material Handling Processes-Manager’s Experience-Accident History

Scoring Model to estimate a plant’s risk for a toxic spill.

5

Scoring Models

A type of Inference Tree which assesses a non-observable variable through other data which can be observed or measured (e.g. the probability of some negative event or the

effectiveness of some complex system).

Purpose: Replace Individual Judgment with a more reliable method.

Risk Index = w(1)RF(1)+ ... +w(n)RF(n)

6

Risk Factors

7

Risk Factors

8

9

Contract to Build a Scoring Model as alternative

to IBC Height & Area Table 503. Frank Noonan reporting to Kate Dargan and Dave

Collins Phase 1: Work with the BFP Features Study Group

as SMEs to build a prototype model. Phase 2: Continuing with BFP Study Group open

model to a larger group of building safety professionals to review and fine tune the model.

Timeframe: 3/8/07 – 2/28/08

10

SSM development for IBC1. Establish SMEs and communication framework.

2. Define risk metric for building safety performance.

3. Define set of risk factors (and scales) for risk assessment, (e.g. occupancy classification, height, area, full menu of active and

passive risk mitigation measures, expected emergency response).

4. Define relative importance of each risk factor.

5. Calibrate Scoring Model for Acceptable Risk on Building Safety Performance.

11

1. Establish SMEs and communication framework.

SMEs: Study Group; Facilitator: Frank Noonan MyWPI is internet forum

Need name and email address of each SME Site Name: BFP Features Study Group

Discussion/ Voting/ Finding Consensus

12

2. Define risk metric for building safety performance Narrative describing Building Safety

(or risk to building safety) Sets transition for defining risk factors. Process: 1st draft today (8/3/07); post for revisions;

complete by 8/24/07. Risk Metric = w(1)*RF(1)+…+w(n)*RF(n)

Scale: [0,10] GAR: GGGGGAAARRRRR

13

Risk Metric Narrative “Building Safety” is defined as the aggregate effectiveness of the mitigation features

((Active and Passive and Emergency Response) in a building that are provided to protect the structure, occupants, emergency responders, and property from losses associated with anticipated hazards primarily due to fire exposure and subsequent collapse.

“Building Safety Success” can be defined as meeting the goals for the reduction

of life and property loss that are acceptable and economically supportable. This

is the core concept of acceptable risk. Acceptable building safety risk is that level of anticipated loss that each entity impacted can accept if a hazardous event occurs. It is based on the probabilities that the various mitigation strategies will perform as intended and it can be measured as a quantitative value, a qualitative value, or both.

Identify and analyze a building’s hazards and the potential mitigations of those

hazards that positively impact building safety and also considers their probability for

successful performance

14

3. Define set of risk factors (and scales) for risk assessment Set of RF: complete, clear, avoid redundancy. Pursue Hierarchical Structure ( i.e. inference tree).

See example on next slide.

Process: 1st draft today (8/3/07); post for revisions; complete by 9/5/07.

Each factor requires a narrative definition and a scale. Whenever possible use objective scale, defining best and worst. [0,1] factors are allowed. Risk factor constraints are allowed as necessary conditions for G or

R.

15

Example from U.S. Navy Vessel Refueling Decision

Major categories Task Difficulty Environmental Equipment Readiness Manpower Readiness

16

Risk Factors 1. Exiting 2. Compartmentation 3. Smoke Management 4. Automatic Sprinklering 5. Fire-Resistive Construction 6. Structural Integrity 7. Better Inspection and Maintenance Compliance 8. Emergency Response 9. Occupancy Type

17

4.

4. Define relative importance of each risk factor. Method of Pair-wise Comparisons

Rank order the set and use least important as anchor to elicit relative importance; repeat using most important as anchor.

Make effort to exploit the hierarchy. Process

Voting: Average and post results Start voting on 9/07/07; post Round 1 results by 9/18/07;

post Round 2 results by 9/28/07. Eliminate factors if weight is less than 1% and more than

15 factors.

18

5. Calibrate Scoring Model for Acceptable Risk on Building Safety Performance.

Create a set of Bldg Design/Operating Scenarios where bldg safety performance is on margin with respect to Acceptable Risk. Each scenario has an SME creator who provides a

narrative and set of risk factor scores. Once a scenario is created other SMEs may weigh

in on scores and make a GAR vote; scenario is eliminated if simple majority vote it as G or R. (cont.)

19

5. Calibrate Scoring Model for Acceptable Risk on Building Safety Performance.

Need Scenarios: My worry is with too few rather than too many.

Each scenario produces a risk index score and their range defines the Amber range in the GAR scale.

Process: Start 10/1/07; complete by 11/1/07.19

20

Review & Fine Tune Prototype Model In Jan/Feb ’08, post the BFP Features Study

Group prototype model for input from larger group of building safety professionals.

Revisions to Constraints on risk factors Relative weights of risk factors Ruling out any scenarios on acceptable risk

margin