Reducing PSM risk in Pharma- OPPI

1. Reducing Process Risk in
Pharmaceutical Industries
Maharshi Mehta, CSP, CIH
International Safety Systems, Inc. Baroda, India and
Fairfield, CT, USA
Maharshi.mehta@issehs.com
www.issehs.com
Seminar on – Emerging Trends in Environment,
Health & Safety Management
ORGANISATION OF PHARMACEUTICAL PRODUCERS OF INDIA
April 2, 2004

2. Agenda
 The Emerging Need for Process Safety
 Hazard and Risk
 Hazard and Hazard Identification
 Process Controls that Reduces Risk

3. Driving Forces
 Plant’s existence
 Harm to people, process and environment
 Process Interruptions
 Regulatory and Corporate Requirements
 Liability
 Return on Investment
 Recovery of resources
 Savings from waste management
 Pollution control at source
 Share holder’s confidence
 Pre-requisite to participate in Global Economy
 Public Image
 Press coverage
 Court decisions
 Major accidents

4. Public Image
Survivors of NC pharmaceutical plant
explosion work in Nebraska
……..” Jan. 29, 2003, blast that killed six
people… "There were a lot of injuries ...
a lot of bad burns, and so many people
in shock," Howard said. "We tried to
help, but most of us just prayed. It was a
miracle of God that so many people
actually walked out of there."

5. KINSTON, North Carolina
(CNN) -- A massive
explosion and fire
Wednesday gutted a
pharmaceutical supply
plant, killing at least three
people and injuring more
than two dozen others --
about 12 of them critically. Authorities
recommended
residents within a
mile radius around
the plant to
evacuate
A volatile mix of air and
suspended dust caused
the explosion The
explosion was so
powerful it blew doors
open on houses more
The stock of West
Pharmaceutical was halted on
the New York Stock Exchange
after the explosion, which is
typical following a calamity
North Carolina Governor

6.  The Occupational Safety and Health
Administration said the plant was inspected in
October, cited for numerous safety violations,
including problems with the electrical systems
design and use, inaccessible fire
extinguishers and hazardous-waste
operations, and fined about $10,000, which
was reduced to about $9,000 early this
month.

7.  North Carolina is the site of one of the
nation's worst workplace disasters:
Twenty-four employees and a delivery
man died and 56 people were injured in
a 1991 fire sparked when hydraulic fluid
from a conveyor belt sprayed over a
gas-fired chicken fryer at Roe's Imperial
Food Products plant in Hamlet.

8.  April 1, 2002 RTE News
 Two men were taken to hospital following an
explosion and fire at a pharmaceutical
company in Rathdrum, County Wicklow this
afternoon.
The two are believed to have suffered facial
burns in the incident. An investigation is
underway at the ABC plant.

9. Economic Impact
 The stock of ABC was halted on the New York Stock Exchange
after the explosion
 resulted in an estimated $150 million in property damage
 On June 30, 2003, two new European explosion protection
regulations take effect. The first, ATEX 95, Directive 94/9/EC
covers equipment and protective systems that may be used in
areas endangered by potentially explosive atmospheres created
by the presence of flammable gases, vapors, mists, or dusts.
The second, known as ATEX 137, lays down the minimum
requirements for improving worker health and safety in
hazardous areas throughout Europe.
 “Ergonomic-related illnesses remain the most frequent illnesses
at ABC Pharma. In 2002, 43% of all illnesses and 65% of all lost
time illnesses were musculoskeletal in nature and resulted in
1,450 lost days.” Excerept from MNC’s annual report
 In 2002, many of our occupational illnesses and injuries resulted
from chemical exposures. For example, the second most

10. Priority AReas
 Driver Safety
 Ergonomics
 Hygiene
 Process Safety
 Safety Engineering
 HIV/HBV exposure controls

11. Accident Occurred
 Acetone bucket caught fire: 10 L
metal container-plastic shoes-
suspended bucket on valve
 2” dia rubber hose used to fill
metal drum with vinyl acetate-
violent explosion (same operation
conducted number of times
without problems): External paints
prevented grounding of the drum
 N2 Purging was not enough: Fire
in Centrifuge, Insufficient N2 flow-
rota-meter 0-60 l/min, what
needed was 150 l/min

12. Accidents Occurred-Contnd.
 SAVASO, Italy-Dioxane
released due to exothermic
reaction. Critical Temp known
was 230C. However it occurred
at 180 C in absence of agitation
 A runaway reaction occurred
when gradual addition of
material and observing
temperature rise was done by
operator in control room. Faulty
temp recorder did not show rise
in temp. Temp increase was
indicated on a six-point recorder
but it was not located at
eyesight level.

13. Accidents Occurred (contnd)
 Instruction-add methanol in waste product after applying
vacuum and breaking it with N2. Instead, TO REDUCE
AMOUNT OF WORK methanol was added directly resulting in
to fire.
 Not realizing that a vacuum/pressure of as little as 0.1 psi
(vacuum of 2.5” wg, same hydrostatic pressure at the bottom of
cup of tea) to 0.3 psi (Press of 8” wg) could collapse/burst a
storage tank. 100 psi (7bar) of compressed air applied to clean
choked line blew lid off.
 Drain valve of dist. column. kept open for longer draining water
and benzene

14. Accidents Occurred (contnd)
 Sucking In occurred in tank because all three flame
arrestors were choked.
 After cleaning of a tank on hot day, vent was closed
with plastic bag to prevent dust coming in. When rain
cooled tank, it collapsed.
 A tank being steamed, sudden rain cooled tank so
quickly that vent could not draw-in air fast enough. 10
to 20” of opening was needed.
 Content was pumped out more than air could get in
quickly because of change in pump.

15. Why it Happened-Commonality
 Because it has not happened in --years, it won’t happen
 Concept of Inherently Safer Process Design was missing-
 Sufficient redundancy not in place, redundancy design flaws or
not working
 Administrative Controls
 Concept of system safety missing-e.g., PHA
 Hazard Realization and Communication
 Consequences of deviation not realized
 Safe Operating Procedures not available or not blended with
Operation Procedures
 Preventive Maintenance often was Reactive Maintenance-
Specifications on what to inspect not known/followed
 Contractors-Weakest link of chain
 ORGANIZATIONAL CONCERNS-e.g., Line vs staff function

16. Good News
 “Working conditions in pharmaceutical plants are better
than those in most other manufacturing plants” BLS
 With the exception of work performed by material
handlers and maintenance workers, most jobs require
little physical effort. In 2002, the incidence of work-
related injury and illness was 3.0 cases per 100 full-
time workers, compared with 7.2 per 100 for all
manufacturing industries and 5.3 per 100 for the entire
private sector.


17. Occupational Health and Safety Hazards
(B2-3)
 Chemical Hazards
 Flammability
 Reactivity
 Toxicity
 Dust Explosions
 Compressed Gases and Cryogenic Liquids
 Physical Hazards
 Noise
 Ionizing and non-ionizing radiation
 Other Hazards
 Cumulative Trauma Disorders (Ergonomics)
 Mechanical Hazards

18. Flammability
Fire Chemistry
Ignition Source
Oxygen Fuel
Definition
Flash Point
Autoignition Temperature
Lower Explosive Limits
Upper Explosive Limits

19. Ignition Sources
Electrical (23%), Smoking (18%)
Friction (10%), Hot Surfaces (7%),
Overheated Material (8%)
Cutting, Welding, Open Flames (4%)
Spontaneous ignition (4%)
 Slow oxidation of low volatile compound
with accompanying evolution of heat in
non-ventilated area
 Static Electricity (1%)

20. Ignition Sources-Static Electricity
Non-Polar materials like hydrocarbons accumulate static
charges readily as they have high insulating values
 22 mJ of ignition energy from walking across a rug,
many hydrocarbons require only 0.25 mJ
 Flow of liquid through pipe, strainers, filters. In one test
charge development with filter was 10 to 200 times high
than without filter
 Settling of conductive phase to non-conductive phase e.g.,
water in oil.
 Splashing of liquid jets
 Ejection of droplets from nozzles
 Stirring and Mixing
 Solid handling-Sieving, pouring, grinding, micronizing,
pneumatic conveying

21. Fires and Explosions - Solvent
Properties
 Methanol: FP=12 deg C; LFL=6.0%; UFL=36%;
Conductivity units=4.4x107 (high relative
conductivity)
 Toluene: FP=4 deg C; LFL=1.2%; UFL=7.1%;
Conductivity units=<1 (very low relative
conductivity)
 Acetone: FP=-17 deg C; LFL=2.5%; UFL=13%;
Conductivity units=6x106 (high relative conductivity)

22. Specific Conductivity of Selected
Chemicals
Liquid Specific Conductivity
mho/cm
Toluene <1x10-14
Xylene <1x10-15
Heptane
Hexane
<1x10-18
Methanol 4.4x10-7
Isopropanol 3.5x10-6
Water 5.5x10-6

23. NFPA and Indian Petroleum Act
Classification of Flammable Chemicals
NPFA
Class I Flash Point < 100 F
 Class IA Flash Point < 73 F (22.7C) and BP < 100 F
 Class IB Flash Point < 73 F and BP >
100F
 Class IC Flash Point > 73 F and BP > 100 F
Class II Flash Point > 100 F (37.7 C) but < 140 F
Class III A Flash Point > 140 F (60 C) <200 F
Class III B Flash Point >200 F (93.3 C)
Indian Petroleum Act
 Class A: Flash Point < 23C, Class B: 23C-65C, Class C:
65 C- 93C

24. Flammability of Selected Solvents
Chemical FP F(C) LEL % UEL % AITF(C) vap press
mm hg
Xylene 85 (32) 1 7 867(463) 10
Phthalic
Anhydride
305(152) 1.7 10.5 1058(570) 0.00002
Styrene 88(31) 0.9 6.8 914 (490) 14.4
Methanol 52 (11) 6 36 867(464) 95
IPA 53(12) 2.2 13.7 750(399) 44
Toluene 40 (4) 1.2 7.1 896(480) 30
Acetone -4(-20) 2.5 13 869(465) 227

25. Flammability of Selected
Solvents (Contnd)
Chemical FP F (C) LEL
%
UEL
%
AIT F (C) VP
mm
/hg
MEK 16 (-9) 1.4 11.4 759 (404) 78
Cyclohexane -4(-20) 1.3 8 473(245) 78
Methylmethacrylate 50(10) 1.7 8.2 435(815) 29
Butyl Alcohol 98(37) 1.4 11.2 650(343) 6
Butyl Cellosolve 143(61.6) 11 127 460(238) 0.8
Butyl Methacrylate 126(52) 0.9 4.9 562(294.4) 6
Butyl Acrylate 103(39.4) 1.5 9.9 4

26. Reactive Chemicals-Characteristics
 High reaction rate
 Reaction rate increases with temperature. Rate of reaction
increases exponentially with increase in temperature. An
increase of 10C roughly doubles the reaction rate in many
cases.
 If the reaction rate and resulting heat are not controlled , an
explosion could occur.
 Heat initiated decomposition could result in explosion e.g.,
certain peroxides
 Light could be initiator of an explosive reaction e.g.,
hydrogen and chlorine reacts explosively in the presence of
light.
 Shock could initiate an explosion, e.g., acetylides, azides,
organic nitrates, nitro compounds and peroxides.
 Picric acid becomes highly shock-sensitive when its normal
water content is allowed to evaporate.

27. Chemical Structure with Explosive
Tendencies
 -ONO2 nitrate R-NO2 aliphatic nitro
 -NH-NO2 Primary nitramine Ar-NO2
aromatic nitro
 -N-NO2 Secondary nitramine -N3
 -NO nitroso =N-X halamines
 -N=N-diazo -C=C-acetylides
 -N=N-S-N=N-diazosulfide
 Organic salts of chlorates, perchlorates,
picrates, nitrates, iodates.

28. Dust Explosions-What is required for Dust
Explosions
 Presence of Combustible Dust
 Min O2 Conc-3 to 15% v/v
 Min Ign Energy (MIE) and Temperature (MIT)
 Right Particle Size
 <particle size, > the explosion pressure -<MIE and MIT
 Rate of pressure rise of polythene dust explosion
increase from 150 to 400bars/s when part.size reduced
from 100 to 25 microns.
 Minimum Explosible Concentrations (MEC)
 MEC for most materials is 10 to 500 g/m3
 10 g/m3 dust concentration looks like dense fog with
visibility of 1Meter.
 Moisture Content of dust: > Moisture, >MIE, MIT and MEC

29. Explosibility Index
Type of
Explosion
Ignition
Severity
Explosion
Severity
Explosibility
Index
Weak <0.2 <0.5 <0.1
Moderate 0.2-1 0.5-1 0.1-1
Strong 1.0-5.0 1.0-2.0 1.0-10
Severe >5 >2 >10

30. Dust Explosion Characteristic of Selected Dusts
Phthalic
Anhydride
Aluminum
Powder
Benzoic acid
Explosibility Index >10 >10 >10
Ignitian Sensitivity 13.8 1.4 5.4
Explosion Severity 1.6 7.7 2.1
Max Expl Press, psig 72 84 76
Rate of Pressure rise
psi/sec
4200 20000+ 5500
Ign Temp C 650 650 620
Ign Energey, J 0.015 0.05 0.02
Min Expl Conc oz/cuft 0.015 0.045 0.03
Limiting O2%, Inert Gas 14% CO2 2%CO2

31. Exposure Limits
 Permissible Exposure Limit (PEL)
 Threshold Limit Values (TLV)
 Recommended Exposure Limit (REL)
 Short Term Exposure Limit (STEL)
 CEILING LIMIT
 Conc. Immediately Dangerous to Life or
Health (IDLH)
 Lethal Dose, Concentration (LD50, LC50)

32. ODOR AS AN AID TO
CHEMICAL SAFETY
CHEMICAL TLV (ppm) AOT (ppm)
Acetone 750 13
Ammonia 25 5.2
Arsine 0.05 0.5
Carbon monoxide 50 100.00
Chlorine 1 0.31
Chloroform 10 85
p-Dichlorobenzene 75 0.18
Ethyl alcohol 1000 84
Ethyl ether 400 8.9

33. ODOR AS AN AID TO
CONTD....
Hydrogen sulfide 10 0.008
Methyl alcohol 200 100
Methylene chloride 100 250
Naphthalene 10 0.084
Ozone 0.1 0.045
Phenol 5 0.04
Toluene 100 2,9
Vinyl chloride 5 3000
m-Xylene 100 1.1

34. Exposure Limits for Selected Compounds
Chemical TLV
ppm
STEL/C
ppm
AOT
ppm
IDLH
ppm
NFPA Rating
H F R
Styene 20 40 0.017-1.9 700 2 3 2
Toluene 50 skin 150 N 0.16-37 500 2 3 0
Xylene 100 150 1 900 2 3 0
Butyl
Cellosolve
25 skin NA 0.1-0.48 700 2 2 0
1-Butanol 50 C Skin 1400 1 3 0
Methanol 200 250 6000
MMA 100 NA .049-0.34 1000 2 3 2
Phenol 5 Skin NA .012-.057 250 4 2 0
MM
TLV- Threshold Limit Value AOT-Odour Threshold Value
NFPA Rating-Hazard Rating H-Health, F-Flammability, R -Reactivity

35. Exposure Limits for Selected Compounds
(Contnd)
TLV
mg/cum
STEL/C
mg/cum
IDLH
mg/cum
NFPA
Rating
H FR
Phthalic
Anhydride
6.1 NA 60 3 1 1
Lead 0.05 NA 100
Chromium
VI
0.05 0.1, 1 C 3 0 1
TiO2 10
Ref: 1998 ACGIH TLVs
N-NIOSH Limits, C-Ceiling Limits

36. Physical Hazard-Noise
 Health Effects:
 Noise Induced Hearing Loss
 Temporary and Permanent
 Increased pulse Rate, Blood Pressure
 Nervousness, Sleeplessness and fatigue
 Health Effects Depends on:
 Sound Level
 Extent of Exposure
 Frequency of Sound (audible 20 to 20K, Hz:
Most Impact around 1000 Hz)

37. Noise -Allowable Levels
Exposure Time
(Hours)
Max Allowable Sound Level
(dBA)
8 90
6 92
4 95
3 97
2 100
1 105
1/2 110
Redusing Time by half will increase the allowable level by
5dB

38. Approximate Sound Levels
Area/Activity Sound Level (dBA)
Normal Conversation 65
Milling Machine 90-95
Tablet Press 80-90
Manual machining 80-85
Power Saw 100-110
Jet Plane 140-150
What will be Total Noise Level if two compressors-Each
Produces Sound Level of 95 dBA?

39. Ergonomics-Cumulative Trauma
Disorders-Back Injuries
 Back Injuries
 50 to 80% of working population affected
 Account for 33 to 41 % of all compensation
cost
 Average Direct cost is about $10000/claim
 Indirect Cost Could be eight times higher
 Causes
 Poor Equipment design Layout and Postures
 Lifting-Turning around while lifting
 Pushing/Pulling
 Prolonged Sitting Standing

40. Why Hazard Identification
“ For every dollar it costs to fix a problem in the
early stage of design, it will cost $10 at flow
sheet stage, $100 at the detail design stage,
$1000 afte r the plant is build and $10,000 to
cleanup the mess after an accident”
KLETZ

41. Hazard Identification
 Can the process/activity pose a threat to health,
safety, environment or property?
 INPUT: Properties of materials, historical
experience, knowledge of process parameters,
management system, available safeguards,
application of analytical methods
 Output: List of potential problem materials,
process conditions, and situations and
understanding of what can go wrong.
 Conclusion: No known hazard exist, known
hazards that can be controlled, sound controls
may not control hazards

42. Hazard Identification (B1.32)
 Accident and Incidence Investigation (B4)
 Accident Analyses
 Incidence Rate (#of lost time accidents x 20,000)/ Total
Manhours
 Frequency Rate ( #of lost time accidents x 106 )/ Total
Manhours
 Severity Rate (#of lost work days x 106)/ Total Man hours
 Comparative analyses among employees, departments,
companies, preceding months and years, for time, nature of
accidents (e.g., burns, inhalation), cause of accidents and
body parts affected by accidents.
 Employee exposure monitoring. Workplace air monitoring.
 Pre-startup survey and scheduled plant audits

43. PROCESS HAZARD
ANALYSIS (B1.32)
 Hazards of Process
 Previous Incidents
 Engineering and Administrative Controls
 Consequence of Failure
 Facility Sitting
 Human Factors
 Qualitative Factors

44. PROCESS SAFETY
INFORMATION
Hazards Technology Equipment
Toxicity Block Flow
Diagram
Construction
Materials
PELs Chemistry Piping &
Instrumention
Physical Inventory Electrical
Reactivity Operating
Ranges
Relief Vents
Corrosivity Hazards of
Deviations
Design Codes
Stability Material Balances
Compatibility Safety Systems

45. Elements of Hazard Analysis
 Implementation Plan
 Process Safety Information
(Hazards, Technology, and Equipment)
 Prioritize the Process Hazard Analyses (PHA)
 Conduct PHA According to Schedule in Standard
 Schedule for Completing Actions Noted During the
PHA
 Operating Procedures
(for each operating phase and for safety systems)
 Certify Current Employees Sufficiently Trained
 Document the Completion and Comprehension of
Training
 Contractor Injury Log

46. Elements of Process Hazard
Analysis..Counted...
 Procedures for Maintaining Mechanical Integrity
 Document Process Equipment Inspections and Tests
 Hotwork Permits
 Management of Change Procedures
 Incident Investigation
 Emergency Action Plan
 Process Safety Management Compliance Audits

47. Hazard Analysis - System Safety
 Job Safety Analysis (JSA)
 Preliminary Hazard Analysis (PHA)
 What-if and What if -Check List
 Hazard And Operability Analysis (HAZOP)
 Failure Mode and Effect Analysis (FMEA)
 Fault-Tree Analysis (FTA)
 Management Oversight Risk Tree (MORT)
 Human Reliability Analysis (HRA)

48. Time Estimate for Hazard Analyses
Analyses Prep Time Evaluation Documentation
Simple Comple
x
Simple Compl
ex
Simple Compl
ex
PHA 4-8 hr 1-3 d 1-3 d 4-7 d 1-2 d 4-7 d
What-if
Chklst
6-12 hr 1-3 d 6-12 hr 4-7 d 4-8 hr 1-3 wk
HAZOP 8-12 hr 2-4 d 1-3 d 1-3 wk 2-6 d 2-6 wk
FMEA 2-6 hr 1-3 d 1-3 d 1-3 wk 1-3 d 2-4 wk
FTA* 1-3 d 4-6 d 2-4 d 1-4 wk 3-5 d 3-5 wk
HRA* 4-8 hr 1-3 d 1-2 d 1-2 wk 3-5 d 1-3 wk
* Model construction requires additional 3-6 d for simple process

49. Available Software for Hazard
Analysis
 PHA: HAZOPtimizer (A.D. Little, MA; PHA-PC,
Primatech, OH)
 What-if: SAFEPLAN (DuPont,CA)
 HAZOP:CAHAZOP, NUS Corp, CA;HAZOP-PC,
Primatech, OH;HAZOPtimizer, A.D. Little;
HAZSEC, Technica, OH;HAZTEK, Westinghouse,
PA;Leader, JBF Associates, TN;SAFEPLAN,
DuPont.
 FMEA: CARA, Technica; FEMA-PC, Primatech,
OH; HAZOPtimizer, SAFEPLAN
 HRA: HRA-PC, Primatech; SHERI, Bettelle, OH.

50. HAZOP EXAMPLE-Rasin Plant-Xylene Feed
Ite
m
No
Deviati
on
Causes Conseque
nces
Safe Guard Action
2.1 High
Flow
Rota Meter
Fails
Feed Valve
Fails-Open
?? Calibrated
quarterly
Inspected
quarterly
Provide excess
flow valve
Low
Flow
No Flow
Other
Than-
MT
Contaminati
n
Reverse
flow

51. CHAPTER 5
PREVENTION AND CONTROLS

52. Inherently Safer Process
Design
 A design incapable of causing injury no matter what you do
 Emphasis on selection of safer chemicals, reducing
inventory, vessels and machinery that can withstand
extreme conditions and not rely on interlocks, alarms and
procedures
 Examples:
 Using continuous process Vs batch process
 Using fixed piping Vs hose connection
 Replacing chlorine with ozone in water treatment
 Use of dryshaft seals

53. Inherantly Safer Process
Design
 Open structure for storage processing of hazardous materials-
Small quantity of flammable causes significant damage in
closed building-In an accidental discharge of butadine in an
enclosed process area of 133’x288’with flammable controls
provided, an explosion caused 46 fatality, 8 by flying debris,
80% of concrete slab blown off
 Use of pallets of flammable solids in place of finaly devided
solids
 Spring Loaded ballvale as drain valve in distillation column.
Operator has to hold the valve open.
 Installation of remotely operated emergency isolation valves

54. Hazard Prevention and
Control-Principles (B2-3)
Substitute
Process Modification
Engineering Controls
Ventilation
Administrative Controls
 Site Safety and Health Plan/Site Controls
 Housekeeping
 Safe Operating Procedures
 Confined Space/Hot Work Entry Permit System
 Lockout/tagout
Personal Protective Equipment

55. Substituted Chemicals
From Product To Working Function
Chlorinated solvents Aquious solution Tablet Coating
Formaldehyde/Glutara
ldehyde
Phenol, Peroxide Disinfectant
10% benzene in
isopropanol
10% toluene in
isopropanol.
Analysis of the intermediate
para-nitrophenol.
Carbon tetrachloride
& chloroform
Replaced by esters and
ketones
Many different analysis
A TLC running fluid-
chloroform 40,
methanol 25, formic
acid 7-has low
threshold limit values.
Changed to a TLC
running fluid, toluene
40, acetone 5, 100%
acetic acid 4.
Chemical analyses.

56. Flammable/Combustible Liquids-
Controls
 Instrumentation used in Determining Explosive Limits
 Keep in covered containers when not in use
 Flammable concentrations to be kept below 10% of LEL
when an ignition source is present
 Grounding and bonding for static electricity protection
 Use of non sparking tools/ intrinsically safe electrical
apparatus and lighting
 Flammable gas supply to include a non-return valve
 Avoid using flexible hoses for transfer. If it has to be used
use one with male female coupling
 Seal-less pumps or mechanical seals

57. FLAMMABLE AND COMBUSTIBLE
MATERIALS : STORAGE ROOMS
 Allowable quantity per Table e.g., 5 gal/sq feet of floor
area when fire protection is not provided and room
fire resistance is 2 hrs
 Intrinsically safe electrical wiring (Class I Div 2)
 Liquid tight room
 Ventilation to provide six air exchange rate per hour
 Provide clear aisle of 3' wide
 Stacking of containers one upon the other over 30 gal
prohibited
 Dispensing by approved pumps or self closing faucet

58. Tank Storage(B3.19)
 Not to overfill-Consider expansion of liquid when heated,
Gasoline expand about .06 F in volume for each 10 F
increase in T
 Measure metal thickness, weep holes, ultrasonic indicators.
 Minimum Thickness (API 650) t=0.0001456*D*(H-1)*S
 Maximum thickness 1/2”Smaller than 50’ dia nominal
thickness 3/16”, >50<120 1/4”.
 API Standard 2000 for venting of storage tanks
 Wire Screen of 40 Mesh, parallel metal plates or tubes are
also used and preferred
 dikes provided with drain pipe with valve closed outside
dikes Dikes > 6’ high not preferred,
 loading rack to be located at least 25 feet away
 Steel support to be protected by 2 hrs fire resistance
covering
 NFPA 11 for Foam system

59. Preferred Diking
St. Tank
Fire Pit
Fire
Wall
Dike

60. Tank Storage
 Leave about 1M depth of liquid when
emptied to reuce fatigue of the
base/wall weld.
 Design vent for ---M3/hr of vapour and
liquid to prevent overpresuring in
overflow situation

61. Unloading of Tank Cars/Trucks of
flammable liquids
 Metallic gauging rod prohibited when ele power line is
within 20’ of tank opening
 DO not locate under power-line, if feasible. Special rules
apply if loading/unloading has to be done under power-line
 Setting of brakes, “STOP....”signs 25’ in front,
 Bottom loading is preferred
 Continuous present of the operator throughout unloading
 No smoking, grounding/bonding connection
 Truck loading rack be kept 25’ of tank, property (for Class I)
 Grounding and bonding
 Applying chocks on wheels

62. Static Electricity Controls
 Bonding and grounding-Ground Resistance
of < 1Mohms adequate
 Min size No 8 or 10 AWG wire ohms
 Metal to metal contact essential (painted
surface)
 Significance of relative humidity: 60-70% is
required.
 Testing conductivity of wire and connections
 Avoid using clothes and shoes made of
certain synthetic materials.

63. Static Electricity Controls
 Avoid free fall of liq by bottom entry or extend fill pipe. Fill
pipe to terminate within 6” from the bottom of tank
 Flow of liquid less than 1 m/s, not to exceed 7 m/s
 Antistatic additives. e.g., Addition of 0.3 to 1 mg/L of Stadis
450 (DuPont)
 Plastics are available with antistatic additives such as
carbon black
 Grounding and Bonding During Charging of solids
 Filters and other ristrictions, followed by long lenghth of
satraght pipe line
 Pipe diameter to be increased after significant
accumulation of charge
REF: Control of Undesirable Static Electricity - BS 5958, 1991

64. Designs to Prevent Fires and
Explosions - Controlling Static
Electricity
 Bonding and grounding (see diagrams on page 224-
228 of yellow book)
 Dip pipes (or deflector tubes)
 anti-siphon holes
 Relaxation time
 consider letting vessels “rest” after transferring low
conductivity solvents
 Avoid open solids charging to vessels containing
solvents (e.g., use of “flapper valves”)

65. Inerting/Purging
 In general O2 concentration to be kept below <8% to
prevent a dust explosion
 Pressure Purging , Vacuum Purging, and Flow Through
Purging
 Pressure Purging-Fast, uses more N2
 Vacuum Purging-Slow Used for small vessel
 Flow thru- when vessel is not designed for
pressure/vacuum
 Condenced HC vapors in vertical N2 purging line from a
tank to reducing N2 valve
 Inspect that N2 supply infact is ocuuring weekly basis by
testing O2 concentration in blanketed area.
 Low pressure N2 alarm to warn about loss of N2 blanketing

66. Designs to Prevent Fires and
Explosions - Inerting Example
 Equation for sweep-through purging:
 Qvt = V ln [(C1-C0)/(C2-C0)]
 where Qv = volumetric flow rate of nitrogen (e.g., ft3/min or L/min.)
 t = total sweep time (e.g., min.)
 V = volume of vessel (e.g., ft3,, L, m3)
 C0 = oxygen conc. of nitrogen (usually assume 0%)
 C1 = initial oxygen conc. in vessel (usually 20.9%)
 C2 = final desired oxygen conc. in vessel (typically 5%)

67. Designs to Prevent Fires and
Explosions - Inerting Example
Example: Given a 1000 U.S. gallon vessel (V = 133.7 ft3 or 3,786
L), a nitrogen purge flow rate (Qv) of 10 ft3 per minute (or 283
L/min.), a desired oxygen concentration (C2) of 5%, an initial
oxygen concentration (C1) of 20.9%, and assuming that the
oxygen concentration in the nitrogen (C0) is essentially 0% --
how many minutes of purging time are theoretically required?
t = {V ln [(C1-C0)/(C2-C0)]} / Qv
t = {133.7 * ln (20.9 / 5.0)} / 10
t = 19.1 minutes

68. Dust Explosion - Prevention
and Controls
 Inerting, Purging, to keep O2 Conc
below MOC
 Suppression
 Explosion Venting
 Process Isolation
 Pressure Vessel Design
 Control of Ignition Sources

69. Fire Protection (B3.15)
 Minimum number of exits
 The average recommended travel distance distance not
to exceed 100’, in Storage area 200’
 Exits not locked - Doors opening outwards-Free/unobstructed
way to exit - Width of exit 30”-Width of an access to exit 36”
 Illuminated Exit signs in place - Emergency lighting (NFPA
101)
 Exits discharging outside building
 “Not An Exit” sign for Doorways not used for exit i.e., closet
 Fire Alarm system

70. Fixed Foam System for Storage
Tanks(B3.12)
 Foam Application Rate: For air foam system, at least 0.1
gpm/sq feet of liquid surface area of tank to be protected
 Duration of discharge vary depending on Foam Discharge
outlet (type 1 or 2) and flesh point of tank content. For
xylene with FP<100F, duration of discharge is 30 to 55
minutes.
 Minimum number of supplementary foam hose stream of 50
gpm required for up to 65’ dia tank is 1. Minimum operating
time is 10 to 30 minutes.
 One discharge outlet required for tank upto 80’ diameter.To
be provided with effective and durable seal, frangible under
low pressure.
 Piping within dike buried or supported for mechanical
damage.
 Foam Control Valves at a minimum distance of 50’, outside
dikes, for tank <50’ dia, one diameter for tank >50’diameter.

71. Peroxide forming agents
 Dating on receipt, testing every 3 Mo to 1
year
 Store in Opaque containers and exclusion of
air preferably by N2 , except Class C agents
provided with inhibitors that need limited
access of air
 Disposal upon peroxide formation, or within
one month of opening or within 1 year after
receipt whichever is earlier.

72. Peroxide Detection Tests
 Add 1 to 3 mL of the liquid to be tested to an equal volume
of acetic acid, add a few drops of 5% aq. potassium iodide
soln., & shake. The appearance of a yellow to brown color
indicates the presence of peroxides
 Addition of 1 mL of a freshly prepared 10% soln. of
potassium iodide to 10 mL of an organic liquid in a 25-mL
glass cylinder should produce a yellow color if peroxides
are present.
 Add 0.5 mL of the liquid to be tested to a mixture of 1 mL of
10% aq. potassium iodide soln. & 0.5 mL of dilute
hydrochloric acid to which Few drops of Starch soln. is
added just prior to the test. If blue or dark-blue color
appears within a minute shows the presence of peroxides.

73. Designs to Prevent Incidents -
Pressure Relief Devices
 Location of Relief Devices:
 consider need for pressure relief on all vessels,
including reactors, storage tanks, towers, etc.
 blocked-in sections of liquid filled piping need
thermal relief
 PD pumps and compressors need relief on
discharge side
 storage vessels need pressure and vacuum reliefs
 vessel jackets may need relief

74. References
 NFPA 654-Standard for the prevention of Dust Explosions in Plastic Industry
 NFPA 63- Standard for the prevention of Dust Explosions in Industrial Plants
 NFPA-Fire Protection Handbook, 5th Edition
 NFPA-101-Life Safety Codes
 NFPA-69 Standard For Explosion Prevention Systems
 The Human Factors Society, Santa Monica California, USA, American National
Standard for Human Factors Engineering of Video Display Terminal Work
Stations
 HMSO, UK, Health and Safety at Work Dust Explosions In Factories, #22.
 Bodurtha Frank, Industrial Explosion Prevention and ProtectionMcGraw Hill,
New York
 Royal Society for Prevention of Accident, UK, (ROSPA) Engineering Codes and
Regulations for Lifting Appliances
 ROSPA, UK Construction Regulation Handbook
 AiCHE, Center for Chemical Process Safety, Hazard Evaluation Procedures,
New York, USA

75. References (Contnd)
 Wood, Fawcett, Safety and Accident Prevention in
Chemical Operations, John Wiley and Sons, New
York
 Hammer W., Occupational Safety Management and
Engineering, Prentice Hall, Englewood Cliffs, NJ,
USA.
 Construction Safety Council, Fall Protection Field
Guide, Hillside, IL, USA.
 ACGIH, Industrial ventilation, Cincinnati, OH, USA.
 Fthenakis, Prevention and Control of Accidental
Releases of Hazardous Gases, Van Nostrand
Reinhold, New Yor, 10003