CHEN 455 Exam 1

Likelihood

A measure of the expected probability or frequency of occurrence of an event -for chemical plants the frequency is most commonly used

Impact

A measure of the ultimate loss and harm of an incident. Example: A 10 kg/s ammonia leak produces a downwind toxic vapor cloud resulting in local evacuations, emergency response, plant downtime and loss of community support.

safety metrics

used to measure effectiveness of a safety program -lagging metrics: data collected after incident occurred -leading metrics: data collected before an incident has occurred

TD

toxic dose -irreversible effect

injuries

toxic releases, eardrum rupture, impacts, pressure impulses, flying fragments

fatalities

toxic releases, flash fires, pool fires, lung hemorrhage, impacts

moderate

use under less hazardous conditions -available energy may be same but passively reduces potential loss event impacts -lower temp, pressures, concentrations etc

8. Operating Porcedures

written instructions for operation that say how to carry out safe operation, explaining consequence of deviation, key safeguards, address special situations and emergencies -write/ revise operating procedures to make more clear and usable -review and update procedures -identify safe operating limits

PEL

Permissible exposure limit -made by OSHA, does have legal authority -regulatory standard- typically similar to TLV-TWA

detoxification

-digestive tract, where chemicals can be converted to less harmful products

Hierarchy of Safety Programs

(best to worst) 5. Adapting-safety is core value of organization and primary driver for success 4. performance monitoring-using statistics to drive continuous improvement 3. management systems-based on such as Job Safety Assessment(JSA), lock-out/tag out 2. Complying- to rules and regulations 1. reacting- to accidents as they occue 0. no safety program- maybe even disdain from safety

Toxicology

-early def: "science of 'poisons'" -harmful to humans cuz intrinsic nature and dose -study interaction of humans w/ chemical or physical agents

Local Ventilation

-Hoods -+ or - pressure to remove contaminants -preferred cuz eliminates/ greatly reduces worker exposure -minimal airflow required -visibility and containment for fire/explosion -assume plug flow for volumetric flow rate -Qv=A(ubar)=LW(ubar) -ubar= avg. air velocity

procedural

-based on established or official was of doing something -administrative controls -policies, operating procedures -safe work practices, LOTO, hot work emergency response sys -training

Blood lvl variations

-concentration gradient -mass transfer -routes of entry: inhalation, absorption, ingestion, injection -biotransformation/ metabolism -accumulation -excretion modes

Respirators

-control of hazards -compromise workers ability and should only be used temporarily, in an emergency, for last resort -standards include fit tests, periodic inspections, correct application, training, recordkeeping (OSHA) -masks, cartridges, canisters, self-contained breathing apparatus(SCBA- dont depend on environment for O2)

Objectives of Toxicology

-estimate effects of chemicals, noise, fires, and explosions etc on humans -dose-response data exist for variety of agents -extend limited consequence data where effects have not been measured -consequences needed to asses and reduce risk -risk=consequence*probability

B. Evaluation of Hazards

-extent of degree of exposures in workplace -take into account existing controls and effectiveness as well as potential process upsets -eval both during design phase and sampling during operation to assess effectiveness of controls -exposures large and small -compare exposure data w/ health standards (TLVs, PELs, IDLH)

7. hazard identification and risk analysis

-identification of hazards and potential consequences -define risk posed by hazards, reduce potential consequences and frequency -qualitative or quantitative analysis -develop/implement corporate methods/ procedures for hazard analysis and risk assessment and develop simulations -lead/ participate in PHA

single exposure dose-response

-lvls of response to toxicants with number or % affected at each dose lvl -responses of large # people follow normal (Gaussian) distribution

4. noise exposure

-measures in decibels (dB) -dB=-10log(I/I0) -log base 10 -sound 10x more intense, intensity lvl 10 dB greater -dbA is absolute sound scale by establishing intensity reference (hearing threshold is set at 0 dBA) -use hours for concentration in calculations and dBA instead of ppm -theoretical limit for 1 atm= 194 dBA

Ventilation

-most common method for control of hazards -used to dilute containment below target conc. and remove before workers exposed -quickly removes dangerous concentrations of flammable/toxic materials -quickly localized, reducing amount of air removed and equipment size -can be added to existing facility -fans, ducts, producing small pressure drop preferably at exhaust pulling out air -local or dilution ventilation

3. Dust Exposure

-particles 2-5 microns have greatest hazard to lungs -nono particles... agglomeration? -larger particles unable to penetrate lungs -smaller particles mostly exhaled, particle aerodynamics -use mppcf

Probit method

-predict % affected by a cause -use normal distribution f(x) to represent dose-response curve -convert dose-response curve to linear data -Y= probit variable to estimate % individuals affected -sigmoidal dose-response curve converted to straight line

2 toxicants

-relative effects can be very dif. at low and high doses -response data needed over wide range to characterize the relative hazards -left most chemical is more toxic typically on a graph of dose vs. toxic response graph

Hazard identification

-relatively easy to identify hazards given specific physical situation -lot more difficult when plant being designed doesnt exist yet -rely on risk based process safety (RBPS) procedures to help

Leading indicators

-response time for process safety suggestions -# workers w/ overdue training -# operating procedures updated each year -work order backlog

chemical absorption

-through skin -rate varies widely w/ chemicals and skin conditions -dermal is the least damaging -lowest conc. in blood PPE, glove selection for control

parameters for toxicological study

-toxicant description -target or test organism -effect or response to be monitored -dose range -period of test -chronic or acute -dose vs. response curve

Relative toxicity

-toxicity degree varies widely w/ differences in agent and susceptibility -wide range shown in table 2-6 for lethal doses of many chemical agents -dose/body weight and intrinsic nature are main parameters

Bhopal Incident

-union carbide (USA) and union carbide india limited (UCIL) joint owned plant -pesticide production plant - methyl isocyanate as intermediate -extreme financial pressure, couldnt sell product -in open country but shanty towns grew around plant- local officers looked the other way -MIC storage tank w/ 16000 gals -had safety measures but refrigeration off to save money, scrubber out of service to save money, flare not working cuz corroded pipeline

Dilution Ventilation

-used when local isnt possible: worker always exposed but diluted conc < TLV/PEL -contaminant in open area and not highly toxic -air used -calculate needed ventilation rate (Qv)

Bhopal Incident Steps

1. MIC storage tank contaminated w/ water 2. MIC & water reacted and heated to boiling point 3. pressure increased and relief device opened and released MIC vapor into atm 4. wind speed low to little dispersion of vapors 5. nighttime so everyone was asleep in shanty town 6. no emergency response pan in place at plant or in community- medical response inadequate -~2500 people killed possibly up to 5000 -20,000 suffered severe exposure effects -settlement of $470 mil -plant just abandoned in place, not cleaned or remedied

AICHE Ethics Statement

1. hold paramount the safety, health and welfare of the public and protect the environment in performance of their professional duties 2. Formally advise employers/clients if they perceive that a consequence of their duties will adversely affect the present or future health/safety of colleagues or public (11 total)

Potential exposures

1. single volatile toxicant 2. multiple volatile toxicants 3. dust 4. noise 5. toxic vapors in enclosure, w/ ventilation 6. vaporization of liquid

Risk

A measure of human injury, environmental damage, or economic loss in terms of both the incident liklihood and the magnitude of the loss or injury. A function of 1. Probability and 2. Consequnce

Consequence

A measure of the expected effects of a specific incident outcome. Example: A 10 kg/s ammonia release resulted in a toxic cloud downtown.

ALCOA

Aluminum Company of America -founded in 1888 by charles martin-affordable way to produce aluminum by electrolysis -largest supply of aluminum in world -industry leading safety program

Hazard

An inherent chemical or physical characteristic that has the potential for causing damage to people, property, or the environment. Hazards are typically always present. Example: A pressurized tank containing ammonia.

Accident

An unplanned event or sequence of events that results in an undesirable consequence. Example: A leak in a pressurized vessel containing ammonia.

DHS

Department of Homeland Security -6 CFR 27 Chemical Facility Anti-Terrorism Standards -risk-based standards for security of chemical facilities -tiered security w/ diff security requirements -chemical security Assessment Tool (CFATS) to determine tier

C. Control of Hazards

Environmental Control: -reducing exposure/ conc. via enclosure, ventilation, wet methods, housekeeping PPE: -providing protection barrier via ear plugs, gloves, NOMEX.... -standard PPE= hard hat, safety shoes, glasses, gloves, ear plugs

EPA

Environmental Protection Agency -40 CFR 68 Risk Management Programs(RMP) -release of toxic or flammable materials that have off-site impacts -consequence analysis if TLV exceeded -prevention program w/ 11 elements

IDLH

Immediately Dangerous to Life and Health -set by NOISH -avoid exceeding these limits

OSHA

Occupational Safety and Health Administration -29 CFR 1910.119 Process Safety Management of Highly Hazardous Material -manufacturing sites when on-site inventories exceed TLV -prevention program with 14 elements

Potential Chemical Plant Hazards

Properties of chemicals: toxicity, flammability, reactivity, biohazards equipment/process: high press, high temp, mechanical functions procedures: normal process operation, vessel entry, hot work permit management: performance monitoring, safety culture, hazard identification -not possible to list all potential hazards

Safety

Strategy for accident prevention - not very well defined.

Incident

The basic description of an event or series of events, resulting in one or more undesirable consequences, such as harm to people, damage to the environment, or asset / business losses. For chemical plants this includes fires / explosions and releases of toxic or harmful substances. Example: A leak of 10 kg/s caused by corrosion of the storage vessel.

voluntary risk

consciously tolerated risk by someone seeking to obtain the benefits of the activity that poses the risk -riding in car, motorcycle, mountain climbing, skiing

societal risk

a group of people exposed to one or more hazards, hazard and group must be carefully defined

10. Asset Integrity and Reliability

activities to ensure important equipment remains suitable for intended purpose -proper selection of materials of constructions, inspection, testing, preventative maintenance, design for maintainability -review/assess data from inspections- draw conclusions and make recommendations -develop/implement practices/procedures/strategies to manage integrity in facility -look up corrosion rates to provide gen guidance for making specs

inhalation

airborne dust conc. can reduce the transfer of gases in lungs -particulates 2-5 micrometers can reach and remain in bronchial tubes and alveoli -ventilation, respirators, hoods, PPE for control

2. Compliance w/ Standards

applicable regulations, standards, codes, other requirements issued by national/ state/ local gov, orgs and the corporation -interpretation and implementation of requirements -participate in standards development -develop sys to identify standards and uniformly administer and maintain info

6. Process knowledge management

assembly and management of all info needed to perform PS activities, and verification of accuracy and up-to-date -info must be readily available to those who need it to safely perform jobs -validate existing P&IDs w/ actual plant config -develop safe operating limits and consequence of deviation -update PS knowledge after MOC -write internal standards for company -develop database for relief devices

lagging indicators

based on accidents that occurred -first aid incidents -loss of primary containment (LOPC) incidents -property damage -injuries -fatalities easier to define and tabulate

4. workforce involvement

broad involvement of operating/ maintenance personnel in PS activities, make sure lessons learned are considered and addressed -organizing workforce involvement effort at all lvls of corporation -supervisor regularly lead discussions around PS concerns/issues w/ operators -worker provide constructive feedback to improve PS and track feedback to resolution

toxicant

chemical or physical agent w/ nature to cause harm to biological system -chemicals, dusts, fibers, noise, radiation etc

conditional modifiers

conditions that occur after initiation and impact a step in sequence either before or after incident -weather conditions, people there, probability of ignition

regulation

developed by gov and has legal authority -may be based on code or standard -violations can result in fines/jail time

Process Safety

disciplined framework for managing the integrity of operating systems and processes handling hazardous substances by applying good design principles, engineering, and operating practices -deals w/ prevention and control of incidents that have potential to release hazardous materials or energy -incidents can cause toxic effects, fire, or explosion and could result in serious injury, property damage, lost production, and environmental impact

enabling conditions

do not independently cause incident, must be present for it to proceed -T or P at certain values, presence of raw material in process

ED

effective dose -minor/ reversible

carcinogens

effects of lvls unknows, zero threshold limit

14. Operational Readiness

evaluation of process before start-up or restart to ensure can be safely started -restart after shutdown or idled and after process changes and maintenance, start-up of new facilities -lead/participate in PSSR -commissioning and start-up plans -identify critical PS info (PSI) required to operate safely -start-up process

storage

fat cells, liver, kidney, bones -fat deposits can later be metabolized w/ release of stored toxins in blood -can cause damage to kidneys, liver, lungs and reduces elimination amounts and efficiency

19. Auditing

periodic critical review of PS management sys performance by auditors not assigned to site -identify gaps in performance and improvement opportunities, track closure of gaps to completion -participate as auditor or audited -develop PS audit methods -manage audit recommendations and make sure they are being implemented

injection

highest blood concentrations -PPE, line of fire for control

15. Conduct of Operations

how operational and management tasks required for PS are carried out in deliberte, faithful, and structured manner -managers ensure workers carry out required tasks and prevent deviations -implement practices intended to maintain operational discipline -work w/ peers to insure performed tasks done correctly over long period of time -monitor actively and make corrective action plans

A. Identification of Hazards

information of interest -potential hazards (vapor, dust, noise..) -entry mode of toxicant (inhalation..) -potential impact(skin, lungs, eyes..) -health info(TLV, reactivity, explosive conc....) Safety Data Sheets (SDS) or MSDS -lists of physical properties of substance that may be required to determine potential hazards -from chemical manufacturers, commercial source, or on-site compilation

toxicity

intrinsic property of an agent that causes a particular effect on a person -Acute: short period of exposure <24 hr -chronic: multiple exposures during long exposure period

excretion

kidney, liver, lungs

18. measurement of metrics

leading/lagging indicators of PS performance, including incident/ near-miss rates and how well key PS elements are being performed -info used to drive improvement in PS -site lead/ participation in collecting and reporting metrics -prepare reports on metrics -develop/ implement site/company metrics

LD

lethal dose -LD50= dose lethal for 50%

toxic hazard

likelihood of a damaging effect from exposure to agent -magnitude can be reduced and controlled by hygiene methods -toxicity cant be controlled

Passive

minimize hazard thru process and equipment design features that reduce either the frequency or consequence w/o active functioning of any device -equipment w/ higher pressure rating -blast walls around equipment to reduce blast overpressures -dikes around storage vessels to contain spills -separation of equipment in plant layout to reduce propagation of impacts

standard

more elaborate than code, explaining in a lot more detail how to meet the code -code says what you need to do and standard says how to do it -no legal authority but might adopt

individual risk

one person exposed to one or more hazards, usually location dependent

16. Emergency Management

plans for possible emergencies that define actions, resources to execute them, practice drills, continuous improvement, training and informing workers/community/stakeholders in event incident occurs -emergency response drills w/ community responders -perform emergency or table-top drills -planning and addressing potential plant emergencies

1. Process safety culture

positive environment where all employees committed to safety -starts at highest lvl of org and shared by all w/ process safety leaders -develop/ deploy corporate process safety culture programs -identify issues in PS culture issues and influence corporate changes -maintain strong PS culture within team mambers -formal assessments to identify gaps and recommend improvements

12. Training and Performance Assurance

pracitcal instruction in job and task requirements/ methods for operators/ maintenance workers, supervisors, engineers, leaders, PS professionals -verification trained skills are being practiced proficiently -develop PS training programs and oversee them -give or receive PS training

20. Management Review and Continuous Improvement

practice of managers at all lvls of setting PS expectations and goals w/ staff and reviewing performance and progress, could be in leadership team meeting or one-on-one -may be facilitated by PS lead but owned by first line -management reviews -evaluate results from reviews and proposed/ reviewed recs for improvements -engage management to follow-up and close out recs

11. Contractor management

practices to ensure contract workers can perform jobs safely, make sure contracted services dont add to/increase facility operational risks -audit contractors -recommendations/ actions to improve contractor performance -develop PS requirements for hiring new contractors

preventative safeguards

prevents initiating event from proceeding to defined, undesirable incident, a protection layer -stops incident from proceeding -basic process control sys (BPCS), alarms/interlocks, operator response, pressure relief sys, maintenance, emergency shutoff valves/ cooling sys, grounding, normal testing/inspection

9. Safe Work Practices

procedures to safely maintain and repair equipment such as permits to work, line breaking, and hot work permits-applied to non-routine operations -confined space operations -certify confined space attendants -develop/audit line breaking, lock-out/tag out (LOTO) and other procedures -corporate work permit policy -audit/improve safe work practices

5. Stakeholder Outreach

process for identifying, engaging, and maintaining good relationships w/ external stakeholder groups -surrounding community, suppliers of raw material, customers, gov agencies and regulators, professional societies, contractors -lead community action panel (CAP) meetings -work w/ local community to create area CAP and facilitate meetings -develop practices/ standards to coordinate and manage off-site accident risks to communicate w/ stakeholders -coordinate emergency response simulation/ drill in community

13. Management of chnage (MOC)

process of reviewing and authorizing proposed changes to facility design, operations, organization, activities prior to implementing them -PS info updated -develop corporate procedures for change management -participate in MOC reviews -author MOC docs -MOC coordinator

minimize

reduce hazardous material or energy quantity -reduces potential accident severity

mitigative safeguards

reduces consequences after an incident has occurred, may already have consequences -active fire protection (sprinklers/ sprays), emergency fire water sys, passive fire protection (insulation), flammable vapor detectors, emergency response, equipment layout and spacing, diking, emergency power, blast walls, water curtains, explosion blow-out panels

simplify

reduces unnecessary complexity -reduces likelihood of an accident

substitute

replace with less hazardous material -reduces/eliminates available chemical energy -reduces/eliminated potential accident severity

17. incident investigation

reporting, tracking, investigating incidents and near-misses to identify root-causes, take corrective actions, evaluate incident trends, communicate lessons learned -participate in incident investigations and manage action items -develop/implement corporate procedures for incident investigation

Active

requires an active response -engineering controls, human intervention also included -alarms w/ operator response -process control sys, safety instrumented sys (SIS), safety instrumented functions (SIF) -sprinklers/ water deluge sys -inerting and purging sys -water curtains to knock down gas releases -flares

involuntary risk

risk imposed on someone who does not directly benefit from the activity that poses the risk -living close to chemical plant, riding train/plane, visiting mall

Inherent

safeguards used to prevent initiating events from propagating into accident w/ consequences -add considerable cost to process -require testing and maintenance - can still fail -design process with fewer hazards and reduce safeguards needed- elimination of hazards rather than depending on controls, interlocks, complex management sys, elaborate procedures -tolerant of errors and often cost effective, simpler, reliable, easier to operate -minimize, substitute, moderate, simplify

code

set of rules developed by team of knowledgeable people. people most likely associated w/ industrial professional org -do not have legal authority but gov might adopt into law

3. Process safety competency

skills and resources company needs to have in right places to manage process hazards -verification of these skills and resources (corporate competency) -develop training program to increase worker lvl of competency -competency profiles to critical process safety positions -evaluate unit to determine gaps

damage

structural damage, glass breaks, fires

Industrial Hygiene

study methods to prevent or reduce exposure and intrusion of toxicants into biological systems

TLV

threshold limit value -max exposure limit to humans for 8 hr/day, 40 hr/week that does not cause a noticeable effect -TWA=time weighted avg -made by ACGIH, does not have legal authority -STEL= short term exposure limit (15 mins) -C=ceiling limit (conc. not to be exceeded at any time) -for flammables, TLV 1/4 of lower flammable limit -ppm or mg/m^3 -dusts: mg/m^3 or mppcf (millions of particles/ ft^3 air)

ingestion

through contamination of food -bile -rules on eating/ drinking/ smoking for controls