Common Defects in Concrete – Causes and Effects ✳️Concrete is a strong and durable construction material, but poor workmanship, improper mix design, or inadequate curing can lead to several defects that affect performance and durability. Understanding these defects helps engineers maintain better quality control on site. 1. Honeycombing Voids or cavities in concrete caused by poor compaction or insufficient vibration, resulting in weak concrete and possible exposure of reinforcement. 2. Segregation Separation of aggregates from the cement paste, usually due to excess water or improper handling, leading to a non-uniform and weak mix. 3. Bleeding When water rises to the surface of fresh concrete due to a high water–cement ratio, creating a weak and porous surface layer. 4. Cracks Concrete cracks may occur due to shrinkage, thermal stresses, overloading, or poor curing, which can reduce durability and structural performance. 5. Spalling Chipping or breaking of the concrete surf...
Chemical Safety in the Workplace
Safe Use of Flammable Liquids
CONTENTS
3.1
Solvents 3
3.2
Fuels 4
4.3
Other hazards of flammable liquids 9
4.4
Incidents involving flammable liquids 9
5
Chemical Safety Programme 11
5.1
Overview 11
6.1
Overview 13
6.2
Factors for consideration in the risk assessment 15
7.1
Overall strategy in establishing safety measures 18
7.2
Elimination/Substitution 19
7.3
Segregation 20
7.4
Engineering control measures 20
7.5
Administrative control
measures 23
7.6
Personal protective equipment (PPE) 23
7.7
Monitoring 26
7.8
Some practical safety measures 28
8.1
Overview 34
8.2
Emergency response plan 35
9.1
Overview 37
9.2
Sources of hazard information 37
9.3
Means of hazard communication 37
10
Information, Instruction and Training 41
10.1
Overview 41
10.2 Information and instruction 41
10.3 Employee training 42
Fire/explosion Data of Some
Flammable Liquids Used in Workplace 44
1
Preface
Flammable liquids are extensively used in work processes such as
printing, surface finishing, paint manufacturing, furniture making and indoor
decoration. They are commonly
found as main components in paints, printing
inks, diluents, etc. Handling and storage of flammable liquids
could create hazards if safety measures are not taken.
Fire and explosion are the main hazards associated with the handling and
storage of flammable liquids. In
addition to physical hazards, flammable liquids can also pose health hazards to
workers.
This booklet aims to provide guidance for proprietors
and managers of workplaces to identify
the potential hazards
arising from the use and storage of flammable liquids and establish a
chemical safety programme to protect the safety and health of workers using
flammable liquids.
1
2
Introduction
2.1
Flammable liquids
2.1.1
Flammability of a liquid indicates its relative ease
to start a fire. It is one of the
main properties used to determine fire and explosion hazards. An important indicator of this property is
the flash point1. Flash points2 of some flammable liquids
used in workplaces are given in Appendix 1.
2.1.2
In Hong Kong, a substance is classified as “flammable”
for legislative control purpose under the Factories and industrial Undertakings
(Dangerous Substances) Regulations if its flash point is below 66°C. However, liquid with flash point not within
the statutory limit (i.e. 66°C) should
not be regarded as totally safe because fire and explosion hazards are still imminent
if the liquid is heated to temperatures above its flash point.
2.1.3
Overseas countries or territories under other
jurisdiction may adopt different flash point criterion from Hong Kong for their
legislative control of flammable substances.
In view of the variance, user has to read the material safety data
sheets of the imported chemicals carefully, since imported products not
labelled as flammable may not be so under the local legislation. In case of doubt, further information
should be obtained from distributor or manufacture
3
Use of Flammable
Liquids
3.1
Solvents
3.1.1
Many solvents used in workplaces are flammable
liquids. Besides being used on their
own as cleaning solvents, diluents, etc., solvents are the main components of
printing inks, varnishes, paints, lacquers, adhesives and asphalt products.
3.1.2
Commonly used solvents include chemicals such as
toluene, hexane, alcohols, glycol ether,
etc. and specially
formulated proprietary solvent blends. Flammable solvents often
pose fire or explosion risk if safety measures for their use and storage
are not observed.
3.1.3
Volatile organic compounds (VOCs) such as benzene,
toluene, hexane, etc. are produced during
work processes in which solvents
are used such as printing, cleaning
with solvents, drying of paints etc. The VOCs released may cause health concern
to workers.
3.2
Fuels
3.2.1
Liquid fuels are flammable substances. Most of the fuels are hydrocarbon products
obtained from fractional distillation of crude oil. Hydrocarbon fuels could be gases, light oils and heavy oils depending
on the carbon chain length as illustrated by the examples below:
|
Fraction |
Carbon chain
length |
Distillation boiling range/℃ |
|
Gases |
C1 – C4 |
Below 30 |
|
Petroleum ether |
C5 – C6 |
35 - 90 |
|
Gasoline |
C7 – C10 |
90 - 200 |
|
Kerosene |
C11 – C16 |
200 - 300 |
|
Diesel oil |
C20 & up |
290 - 380 |
|
Heavy oil |
C30 |
250 &
up |
3.2.2
Gasoline and diesel are mainly used for propelling
engines including the aeroplane jet engines that require special grade
products. Diesel is also used in
firing boilers and kerosene is used as fuel in cooking stoves.
3.2.3
Methyl alcohol is frequently used as a fuel for
various purposes such as heating food in catering establishments.
4
Hazards
4.1
Fire and explosion
4.1.1
Fire and explosion are the main hazards associated
with the use, transport and storage of flammable liquids. For a fire to start, the following
conditions are simultaneously required:
l fuel (gas,
vapour or combustible dust) of concentration within the flammable range
l
oxygen (sufficient supply)
l
ignition source
4.1.2
The burning requirements provide a conceptual basis
for establishing safety measures in handling flammable liquids. Elimination of any one or combinations of the requirements
would normally prevent fire.
4.1.3
The above concept
should be applied
cautiously. No ignition
source is needed if a
flammable liquid is heated above its auto-ignition temperature3, and no additional
oxygen is required if an oxidizing agent is present or in some cases when
oxygen is within the fuel molecule (e.g. ethylene oxide).
Flammable liquid burns when the
vapour released from the liquid ignites and the flame propagates. The amount of flammable vapour given off has significant effect on the extent of fire or explosion hazard. Physical properties data of the
liquid such as flash point, viscosity, vapour pressure, flammable range, etc.
provide reference information to identify and assess potential
fire hazards. Data for some flammable
liquids are tabulated at Appendix I for reference.
4.1.4
A combustible mixture
will burn within its flammable
range, which is the
range between the lower and upper flammable/explosive limits 4 . Typical
values of liquid flammable range are given in Appendix I. Flammable range data
shall be regarded as reference information to identify and assess potential
hazards since the conditions can be different from the experimental conditions
used to obtain the data.
4.1.5
Flammable liquid auto-ignition temperature can be used as a reference to evaluate the level of hazard
that will be incurred when the liquid is operated in work processes at elevated
temperatures. It should be noted that
the auto-ignition temperature shall not be regarded as a clear cut-off point
between no ignition/self-ignition conditions
4.1.6
Flammable liquids of low viscosity such as thinners
could be much more hazardous as the liquids
could spread quickly
when spilt, causing a rapid build-up of flammable
vapours from the liquid surface. Furthermore, the vapour pressure5 of a
flammable liquid should also be considered in assessing hazards. The vapour
from the liquid is “pushing” against the atmosphere in the evaporation process. As such, the higher the vapour pressure, the
faster a liquid evaporates. When the
vapour pressure comes to the atmospheric pressure, the liquid reaches its
boiling point and the temperature of the liquid is the boiling point temperature. Vapour pressure
and boiling point
have an intimate relationship. In general, low boiling point liquid will
have high vapour pressure at atmospheric condition. Flammable liquid of high vapour pressure is readily volatile and
thus a high concentration of the flammable vapour could quickly form in the
space above the liquid creating a hazardous environment.
4.1.7
The physical environment where flammable liquids are
handled is an important factor in assessing hazards. Flammable vapour may build up in poorly ventilated areas to a
concentration within its flammable range. As the vapour is heavier than air in many cases,
it will therefore tend to accumulate in lower
areas or in confined spaces such as pits and drains forming potential hazardous
areas. Vapour can also spread away
from the liquid and if ignited at some distance from the emission source, the
flame could flash back to the flammable liquid and starts a fire.
4.2
Ignition sources
4.2.1
In workplaces, various ignition or energy sources can
ignite a flammable/vapour mixture but some of which may seem insidious and obscure to the unsuspecting
workers. A list of ignition sources
is tabulated below for reference:
|
Sources |
Examples |
|
1. Thermal Flames Hot surfaces |
Pilot light,
cigarette lighter, stove,
blow torch, welding Hot
plate, drying oven, molten metal or glass, electric heater, vehicle exhaust,
steam pipe, refractory lining, incandescent particles from incinerator
or chimney, glowing ember, hot slag, cigarette butt, electric lamp, soldering
iron |
|
2. Electrical Electrical current Electrostatic charge Lightning
Stray current |
Electric motor, vehicle starter, electric
switches, cable break, spark produced under short circuit or other fault conditions Pneumatic conveying of solid, flow
of liquid in pipeline,
rubbing of plastic or rubber, liquid spray generation, powder flow, fluidized-bed
drying Direct strike, induced
voltage Arc welding |
|
3. Mechanical Friction heat Materials fracture |
Abrasive wheel, bearing, jamming of material,
piston movement Cracking of metal |
|
4. Chemical Exothermic reactions |
Vigorous oxidizing reactions, exothermic
polymerization and exposing pyrophoric substance (e.g. sodium metal etc.) to air |
4.3
Other hazards of flammable liquids
4.3.1
Apart from the heat released, burning of flammable
liquids may also produce toxic substances e.g. carbon monoxide
and hazardous smoke. As oxygen is consumed during
burning, hazardous oxygen deficiency environment will develop in a confined
area.
4.3.2
Flammable liquids e.g. hexane, toluene,
etc. can pose health hazard if
they enter into human body through inhalation, ingestion or contact with skin. Exposure to flammable liquid may cause
skin irritation, sensitization or dermatitis, or damage to the central nervous
system and organs such as liver, etc. Some flammable liquids
are also known to be carcinogenic. For detailed hazard information, users may
have to consult Material Safety Data Sheets or the supplier.
4.4
Incidents involving flammable liquids
4.4.1
Improper handling of the liquids often leads to fire
and explosion incidents. In general,
the incidents may occur during the following operations:
l
transporting flammable liquids;
l
decanting or dispensing flammable liquids;
l using flammable
liquids in processes
such as mixing and spraying;
l
dealing with flammable
liquids spillages;
l
disposing of flammable
liquids;
l
emptying tanks containing flammable liquid residue;
l cutting/welding
of containers/tanks that contain flammable liquid residue/vapour.
4.4.2
There are many causes of incidents in work processes. It is not unusual that the occurrence of
incidents is a result of random combination of the various causes.
The following are some causes of
incidents involving flammable liquids:
l
lack of information and alertness of the hazardous
properties of the flammable liquids;
l
operator error due to inadequate supervision or lack of training;
l
inadequate control of ignition sources;
l
use of inappropriate equipment in work process
involving flammable liquids;
l
occurrence of electrostatic discharges.
5
Chemical Safety Programme
5.1
Overview
5.1.1
To ensure the safety and health of employees engaged
in the use and storage of
flammable liquids, a carefully planned chemical safety programme is essential. In the programme, the chemical hazards of
flammable liquids should be firstly identified. The risks arising from these
hazards are assessed
taking account of the work situations and personnel involved. Appropriate preventive and/or control
measures are then set up to eliminate or mitigate the risks, with their effectiveness being regularly monitored
and reviewed. The associated
hazard information and protective measures
should be communicated to all affected employees. The chemical safety programme should also include
other elements like planning of emergency responses and training of employees.
5.1.2
The chemical safety programme should be organized and
integrated into the overall safety management system of the workplace to
facilitate its effective implementation. Employers
should deploy adequate manpower and resources for the development,
implementation and maintenance of the programme.
5.1.3
The advantages of establishing a chemical safety
programme at work are as follows:
(a)
to avoid possible
problems or failure
due to oversight of hazards that may be caused when any of
the interrelated processing steps is changed;
(b)
to provide management with a systematic overview about
the entire processing work, allowing easy detection of warning signs of potential incidents; and
(c)
to render a safer operation consistent with increased
efficiency and productivity.
5.2
Major elements
5.2.1
A chemical safety programme should include the
following major elements:
(a)
risk assessment -- to identify the potential hazards
arising from the materials and processes involving the use of flammable liquids
and to assess their associated risks taking into account the adequacy and
effectiveness of existing control measures;
(b)
safety measures -- to adopt and maintain preventive
and/or control measures to eliminate the risks or minimize them to acceptable
levels;
(c)
emergency preparedness -- to establish plans and procedures for emergency response;
(d)
hazard communication -- to establish appropriate and
effective means to disseminate the safety and health information on the
materials and processes to employees via adequate instruction and training; and
(e)
monitoring and review -- to monitor the effectiveness
of the adopted safety measures with regular review and revision which may also
be required for any new requirements or significant changes in the materials or
processes.
5.2.2
Depending on individual situation of the workplace,
employers may find it beneficial to include other elements such as inspection, accident investigation and health surveillance in the chemical
safety programme.
6
Risk Assessment
6.1
Overview
6.1.1
Risk assessment is a process to estimate the level of
risk and decide whether the risk is tolerable or acceptable. Before risks can be assessed, the hazards
related to the process and associated chemicals have to be identified. The risks are then estimated in terms of the people who might be involved and their exposure, the likelihood and
potential consequences of the identified hazards. Suitable safety measures will then be developed and implemented
with periodic monitoring and reviews.
6.1.2
It should be noted that many of the materials used in
industries are proprietary prepared formulations and their chemical
components may not be shown in detail on their original
containers. It is advisable to be
acquainted with the specific functions of the product since these will often
throw some light on their chemical natures. In
all cases, employers who use chemicals should enquire from the supplier
detailed hazard information and user safety precautions of their products.
6.1.3
Reference should be made to relevant legislation,
codes of practice, guidelines and best trade practices
in order to decide on the need and
adequacy of safety measures. Employers
should keep an inventory of all substances in the workplace,
identify whether they are hazardous and ensure that they are handled and stored safely.
It is also essential to obtain
the Material Safety
Data Sheet (MSDS)
of the chemicals from the supplier,
as it contains a wealth
of information indispensable for risk assessment,
stipulation of safety measures and emergency planning.
6.1.4
The risk assessment should be reviewed regularly and
whenever there is any indication to suspect that it is no longer
valid or when there
has been a significant change in the operation to which the assessment relates. In particular, the risks associated with
the processes and chemicals should be re-assessed when:
(a)
there are changes
to any of the processes
or their scales;
(b)
there are changes
in the materials used; or
(c)
safer procedures or improved preventive measures
become available or reasonably practicable in light of recent technological
advancement.
6.1.5
When health risk is assessed,
the occupational exposure
limits (OELs) of the
chemicals concerned should be consulted. OELs
refer to the airborne concentrations of individual chemicals below which no
adverse health effects would be imposed on nearly all workers upon exposures by
the route of inhalation. More
information on OELs can be found in the Code of Practice on Control of Air Impurities (Chemical Substances) in the Workplace issued by
the Labour Department.
6.1.6
As OELs do not represent ‘no effect’ levels at which
every employee can be guaranteed protection, employers should:
(a)
ensure the workplace
exposure standards are not exceeded under normal operational
conditions; and
(b)
keep the level
of exposure as low as reasonably practicable.
6.1.7
Risk assessment should
be performed by competent persons
who are well knowledgeable
about the hazards associated with the chemicals and related processes including the physical and chemical changes
at each stage of the processing work. Specialist or expert advice should
be consulted whenever needed.
6.1.8
The Chemical
Safety in the Workplace: Guidance Notes on Risk Assessment and Fundamentals of
Establishing Safety Measures published by the Labour Department
provides detailed information about the systematic approaches for conducting
risk assessment related to chemical hazards.
6.2
Factors for consideration in the risk assessment
6.2.1
Various factors discussed in paragraph 6.1.4 should be
taken into consideration in assessing the risks associated with the use of
flammable liquids. In addition, the
following aspects are relevant.
6.2.2
Physical form of flammable liquids
The physical form of flammable liquids has pronounced effect on the
extent of the hazards. Flammable
liquids in the form of a mist or froth would increase the risk of fire and explosion. The risk of entering into the human body also increases.
6.2.3
Chemical changes
If chemical changes occur in the process involving the use of flammable
liquids, the chemical reactions and products should be studied, and the
associated hazards should be identified. Incompatibility of flammable liquids
with other chemicals, such as oxidizing agents, should be evaluated to avoid
accidental contact, which would further increase the fire/explosion risk. Attention should also be paid to any
possible side reactions and by-products for example combustion of flammable
liquid may produce carbon monoxide and degradation of high molecular compounds
to produce volatile fractions that may increase fire risk.
6.2.4
Temperature changes
Increase in temperature will accelerate liquid
vapourization. Many of the exothermic chemical changes
generate heat spontaneously resulting in the following effects:
l causing evolution
of hazardous vapours.
l increase of pressure in the container causing explosion.
l rapid bubbling causing splashes
of flammable liquids.
l
increase in reaction
rate generating more heat.
The above effects due to temperature changes will be intensified if there
is no effective means to dissipate the heat evolved, causing localised heating
or superheating of the flammable liquids leading to a
violent sudden expansion.
6.2.5
Scale of the process
Scale of the process generally determines the amount of hazardous
flammable liquids involved. The
larger the amount of hazardous liquids is used, the greater is the likelihood
of occupational exposure and risk.
6.2.6
Extent of exposure
The extent of exposure of employees to hazardous chemical liquids and vapour
associated with the use of flammable liquid
is affected by:
(a)
frequency and duration
of exposure;
(b)
rate of generation and concentration of the hazardous
vapour in the atmosphere; and
(c)
effectiveness of safety
measures in minimizing the exposure.
6.2.7
Working environment and facilities
Many workplaces are temperature and humidity controlled environment to ensure the quality of products, e.g. printing workshops. The working environment may
cause accumulation of hazardous chemicals in the atmosphere if the ventilation
is inadequate. Employers should therefore pay due attention, but not limited,
to the following when conducting the risk assessment:
(a)
any nearby ignition
sources when flammable liquids are handled, transferred or mixed;
(b)
adequate ventilation of the workplace;
(c)
any accumulation of flammable vapours
at locations;
(d)
whether the flammable liquids, when used,
transferred or stored is sensitive to air, moisture or
light, and whether it is compatible with others when stored; and
(e)
proper design of the containers for flammable liquids.
7
Safety Measures
7.1
Overall strategy in establishing safety measures
7.1.1
The primary consideration is to adopt appropriate
preventive measures such as by elimination or substitution in order to directly
remove the hazards at source. On many
occasions, flammable liquids, equipment or process can be replaced by a safer
one that eliminates or minimizes the risks to acceptable level. If such measures are not possible,
segregation of the flammable liquids or the processes or other control
measures should be taken. The use of personal protective equipment should
only be considered a supplementary means or as the last resort to minimize
workers’ exposure to the hazards.
7.1.2
Safety measures can be realised by engineering and
administrative controls. Engineering
control measures such as installation of suitable types of ventilation can
eliminate or lower the level of flammable vapours at source. Administrative control measures such as by implementation of safe work
practices and scheduling of breaks or rotating
shifts can limit worker's time spent near the hazard thus reducing their exposure. The adoption of good housekeeping
practices could not be more emphasized when flammable liquids
are concerned.
7.1.3
It is desirable to consider safety
and health aspects
of the materials, processes and equipment
at the design or purchase
stage. This will save additional expenses and often
reduce practical difficulty in subsequent adjustments to accommodate the safety
features. Management should also keep abreast of the up-coming safety
alternatives or devices that are available on the market.
7.1.4
All safety measures should be documented, for example,
in the standard operating procedures (SOP), and should
be made known to the workers
concerned. The effectiveness of such measures
should be constantly monitored and reviewed to ensure adequacy of the
adopted safety measures. If any
changes are made to the SOP in respect of the use of flammable liquids, a fresh
risk assessment should be conducted
and any amended protective measures
should be documented in the SOP accordingly.
7.2
Elimination/Substitution
7.2.1
Elimination/Substitution of flammable liquids
The three conditions needed simultaneously for the burning of flammable vapour are fuel (concentration within the flammable
range), ignition source and oxygen. Eliminating any one of the above
elements can stop burning and prevent the outbreak of fire. Substituting with
other liquids, which are either non-flammable or have a higher flash
point, could be suitable alternatives, but care must be
exercised in choosing
one that does not pose a risk to health or the environment. In any case, the use and storage of
flammable liquids should be kept to the minimum required.
7.2.2
Elimination of ignition
sources
The elimination of another condition, ignition sources, can prevent the outbreak of fire. Paragraph 4.2 tabulates some common
sources of ignition that should be avoided as far as possible. In paragraph 7.8, precautions related
to elimination of ignition sources
will be discussed in more details.
In some cases, it is possible to replace oxygen
by inert gases
such as carbon dioxide
or nitrogen that does not support combustion in order to reduce fire hazard. Flammable solvents used in batch processes
in the industries could be rendered safe by operating in an inert gas
environment. However, appropriate
control measures should be implemented since inert gas may cause asphyxiation.
7.3
Segregation
7.3.1
Segregation by fire-resisting partitions to isolate
areas where flammable liquids are used,
handled or stored from other parts
of the workroom could be adopted to mitigate fire hazard. However, excessive amount of flammable
liquids should not be stored in the workplace.
In case of such need, Fire Services
Department has to be
consulted for construction of a dangerous goods store in accordance with the licensing requirements and related
guidance.
7.4 Engineering control
measures
7.4.1
The primary objective of adopting engineering control is to eliminate or lower the risks at source. With working processes, the main
engineering control method against hazards of accumulation of flammable vapours
is exhaust ventilation, which provides an effective means of preventing their
accumulation in the atmosphere. There are
four major types of ventilation, namely, general dilution ventilation, booth
ventilation, local exhaust ventilation and push-pull ventilation. The system
should be designed
and constructed to take account
of the flammable hazard of
the chemicals extracted and discharged.
7.4.2
Practically the ventilation methods to control
inhalation and fire/explosion hazards are combined. Factors related to the materials used, such as the quantity,
frequency of use, volatility, flash point, explosive limits and exposure limit
should be considered. Effective
engineering set-up should not only ensure that the workplace is safe regarding
the physical hazards such as fire or explosion, but also safeguard workers’
health.
Ventilation – General
dilution ventilation
7.4.3
In general dilution
ventilation, fresh air is supplied
to work area by using suitable equipment such as fans to
dilute the air containing flammable vapour. Alternatively,
the contaminated air could be drawn out by exhaust fan. Natural airflow
through doors, windows
or other openings such as relief openings
could also be means to dilute the contaminated
air in work area.
7.4.4
This method only replenishes fresh
air supply for the whole
work area. It should
therefore be used in conjunction with other means of ventilation in order to
remove airborne contaminants from source.
Ventilation – Booth ventilation
7.4.5
Booth ventilation is the most effective in the control
of flammable vapour. A carefully
planned and designed
ventilation system in a booth restricts the hazardous activity
to a designated area to contain hazards.
Ventilation – Local exhaust ventilation
7.4.6
Local exhaust ventilation (LEV) allows vapours be
captured and removed by forced air current through a duct near the emission
point before the flammable vapour can be dispersed into the work area. It is
generally applied to the equipment that cannot be readily enclosed. LEV may not
be suitable for working with large pieces of equipment.
7.4.7
When LEV is adopted it is important to ensure that the exhaust
current does not pass through the worker’s breathing zone. The extraction hoods should be positioned
as close as practicable to the point of generation of vapour and should enclose
the source to the greatest practicable extent.
7.4.8
The ducting should be of adequate diameter, and as
short and as straight as practicable. Bends
should be of gentle radius while ‘T’ section junctions should be avoided.
7.4.9
The system should vent to a safe place in the open air
in such a manner that neighbours are not subjected to nuisance. If vents are poorly sited, discharged
vapour may re-enter buildings through doors, windows, roof spaces or intakes to
air conditioning system. In some
cases the air may need to be cleaned before it is discharged to the outside
atmosphere.
Ventilation – Push-pull
ventilation
7.4.10
Push-pull ventilation system
is suitable for large work pieces, in which
fans are used to blow vapours away from the worker’s breathing zone towards an extraction system. Again, the design of the system
should ensure that the flow of contaminated air is not within the
worker’s breathing zone.
7.5
Administrative
control measures
7.5.1
Administrative control measures include arrangement of
work schedules and stipulation of safe work practices so that the risk of
exposure of individual employees to flammable liquids can be reduced. Employers should ensure that these are
incorporated into the management system as far as practicable. Typical safe work procedures that reduce
the worker's exposure to flammable liquids should include the following:
(a)
ensuring the time spent near the hazard is kept to
minimum. Workers should not stay between the work piece and the extraction
system during operation;
(b)
keeping pots or bottles of flammable liquids closed
when not in use;
(c)
avoiding skin contact
with flammable liquids;
(d)
keeping minimum amount of flammable liquid for use in
the workplace, usually no more than a half-day’s or one shift’s supply; and
(e)
adopting of general
practices of good housekeeping.
7.6
Personal protective equipment (PPE)
7.6.1
The primary objective of using PPE is to supplement control
measures by minimizing worker’s
risks of exposure
to flammable liquids
through inhalation or skin contact. Being
only passive protective measures PPE should not replace preventive measures and in general, it should
be considered as the last resort in respect of the safety measures outlined in
this section.
7.6.2
Appropriate PPE should be chosen with regard to the
hazards and physical nature of the chemicals and their routes of entry into the
human body. The MSDS information and
risk assessment will help determine the PPE requirements. Before and after use, PPE should be inspected for any signs of damage.
It should be regularly cleaned and stored in good condition. Contaminated PPE should be properly
treated or disposed of as appropriate, and replacement sets kept readily available. Moreover, as no PPE will give long-term protection, a programme should be in place for its regular
replacement.
7.6.3
Wrongly selected, improperly used or maintained PPE
may do more harm than good as the user may have a false sense of security.
Readers should refer to Chemical Safety in the Workplace: Guidance Notes on Personal Protective Equipment for Use and
Handling of Chemicals for details.
Protective clothing
7.6.4
Protective clothing protects the skin or personal
clothing from contact with flammable liquids and prevents spread of
contamination. When handling
flammable liquids, such as dispensing and storage, or conducting work processes
involving flammable liquids, employees should always wear suitable protective
clothing. Employers should also
provide their employees with special clothing for use in emergencies.
7.6.5
Protective clothing includes gloves, aprons, gowns and
overalls. It is important to choose
protective clothing made of materials that resist penetration or damage by the
chemicals used.
7.6.6
As workers frequently have to handle many flammable
liquids by hands, chemical resistant gloves have to
be used. It should be noted that
natural rubber gloves are not effective against hydrocarbon-type solvents as
they can penetrate the rubber and physically degrade it. Nitrile or neoprene
gloves, though more expensive, should be used against hydrocarbon-type solvents. It is prudent to always check with the
supplier and consult the MSDS of the chemicals involved.
Face and eye protection
7.6.7
Where there is a reasonably foreseeable risk of eye injury,
suitable eye protectors or
face shields should be worn. Safety
spectacles can be fitted with prescription lenses if required, while clear
plastic safety goggles that completely enclose the eyes provide superior eye
protection. If protection to the
whole face including mouth, nose and eyes is required or there is a risk of
splashing, face shield should be used.
Respiratory protective equipment
7.6.8
Respiratory protective equipment (RPE) protects
workers against exposure to dusts, gases, fumes and vapours, but exposure
duration should be kept short.
7.6.9
RPE should be used to protect the workers where engineering control is not reasonably practicable such as during
maintenance work, cleaning, or emergencies where hazardous vapour is generated
from chemical spillages or inadvertent mixing of incompatible chemicals.
7.6.10
The choice of RPE depends on the vapour concentration,
duration of exposure and physical and chemical nature of the flammable liquids.
For fire and other major emergencies where asphyxiation or inhalation
of toxic gases at levels immediately dangerous to health or life is possible, self-contained breathing apparatus (SCBA) should be used.
7.6.11
The following RPE can protect against airborne
chemical contaminants:
(a)
air purifying respirators – when fitted correctly,
most half-face respirators and full-face equipped with appropriate filters
could reduce the exposure to air contaminants by 90% and 98% respectively; many
powered air-purifying respirators that use battery-operated motor
blower to draws air through
filters have similar
efficiency.
(b)
airline respirators – airline respirators supply clean
air to the mask, helmet or hood using an airline, and the device could reduce
the exposure to air contaminants by 96% to 99.9%, depending on the type of
covering.
7.7 Monitoring
7.7.1
Monitoring provides a means to ensure the
effectiveness of safety measures taken. Air
monitoring generally involves measuring the concentration of chemical vapour
at strategic locations in the work area
or at the worker’s breathing
zone. The monitoring can be continuous or periodic sampling and analysis using sensors (with alarm
device), direct-reading meters, static samplers and personal samplers.
7.7.2
Based on the work activities and the result of risk
assessment, the management should establish and implement appropriate
monitoring programme to ensure
that the levels
of chemical vapour
do not exceed the acceptable hazard
limits, such as the lower explosive limit (LEL) or the occupational exposure limit (OEL)
of the chemicals. The monitoring
programme should include:
(a)
monitoring parameters such as concentrations;
(b)
frequency of monitoring;
(c)
location and method of monitoring;
(d)
alarm levels based
on the acceptable limits; and
(e)
follow-up actions.
7.7.3
Investigation of serious accident or dangerous
occurrence involving flammable liquids is a reactive
means of monitoring after the event.
All such events should be investigated and be taken as a ‘learn-from-mistake’ exercise.
The investigation should
be led by a line manager or professional having
adequate knowledge about the operation.
7.7.4
Biological monitoring can be used to provide
additional information for the assessment of chemical exposure by measuring the
level of the chemical or its metabolites (what
it breaks down into in the body)
in the worker's urine
and/or blood. Biological monitoring should be used only to complement, rather than replace,
air monitoring. It can be
incorporated into the health surveillance programme where appropriate.
7.7.5
Health surveillance is a means of early monitoring for
adverse health effects resulted from chemical exposure. It provides clues
on the need of workplace and practical interventions, thereby
preventing further harm to the health, especially for employees who have
regular exposure to flammable
liquids. It usually takes the form of pre-employment and periodic medical
examinations. Where appropriate,
medical examination should also be conducted upon and after termination of work and upon resumption of work after prolonged
sickness absence. Health surveillance should be conducted by registered medical
practitioner, preferably one who has received formal training in occupational medicine.
7.7.6
If monitoring reveals over-exposure to flammable
liquids, the process should be suspended and the causes be investigated. The management should also put in place
suitable control measures and ensure that such measures are operating
effectively before allowing resumption of the process. The lesson learnt
is also useful in reviewing the chemical safety programme.
7.8 Some practical safety measures
7.8.1
The systematic management approach of establishing
measures to ensure safety in the use of flammable liquids has been discussed in
other paragraphs of this section. Some
practical precautions will be suggested in the following paragraphs. It should be noted that these precautions
are only exemplary, as the hazards dealt with may vary from workplace to
workplace. The systematic management
approach should always be adopted to establish suitable safety measures.
Control of ignition source
7.8.2
With respect to the ignition sources discussed in
paragraph 4.2, practical measures can be adopted to avoid them. Some of the sources are discussed in the
following paragraphs.
Electrostatic charge
7.8.3
Electrostatic charge can build up due to liquid
movement in work process, for example, during pumping, emptying, filling and
spraying; and the movement of other materials, such as powders. Incidentally, non-conducting footwear and
clothing made of synthetic fibres could also generate electrostatic sparks that
could be potential ignition source.
7.8.4
In a work environment with potential fire or explosion
hazards, all metal (or other conducting) components
should be adequately earthed in order to protect against electrostatic charge
build-up. All fixed equipment used to
handle flammable liquids should be electrically bonded together and earthed.
7.8.5
Pumping of flammable liquids should restrict to
appropriate speeds in order to reduce possibility of generating electrostatic
charge.
Friction sparks
7.8.6
Tools and work process involving rubbing or impact can
generate sparks. It is recommended to
use spark-proof tools and remove all flammable liquids or residues before
carrying out operations that may generate spark.
Hot work
7.8.7
Welding, cutting or similar hot work operations can be
a potential source of ignition for flammable liquids. In many incidents, hot work causes fire or explosion. The hot work should only be carried
out under strictly controlled
manner with safety measures in place.
7.8.8
Before hot work is carried
out, flammable liquids
in the vicinity should be
removed. When working on containers
that have been used to contain flammable liquids,
any remaining liquids
should be drained
off and residues should be cleared.
Flammable vapour inside containers
should be removed by flushing with air. Accumulation
of the flammable vapour in the workplace should be avoided.
Electrical equipment
7.8.9
Electrical devices should be avoided as far as
possible inside a flammable atmosphere since any spark given off would set off a fire or explosion. However, if the situation so requires, special types of
protection, for example explosion proof6,
intrinsically safe7, enclosed type equipment8, etc. can
be considered. However, to ensure
that these equipment live up to their expected
functions, they have to fulfill recognized international or
national standards, such as the BS EN 60079:2004 series.
6 This is the equipment that is housed in an enclosure capable
of containing an internal explosion without allowing flames or hot gases to
escape to trigger an explosion in a flammable atmosphere.
7 This is the equipment that does not release sufficient
electrical or thermal energy to cause ignition of flammable vapour in a
hazardous area.
8 The
equipment has electrical components that are fully encapsulated in an approved
material so as to exclude the flammable atmosphere.
Explosion venting/relief
7.8.10
Flammable vapour may explode when ignited. Explosion venting/relief is a passive
protection measure whereby the drastic pressure build-up in a closed vessel or
system is released through a setup without causing the vessel or system to
rupture by the force in flammable vapour explosion accident.
7.8.11
One such application is the installation of explosion
relief panel in solvent evaporating oven. The
relief panel is designed and constructed such that the explosion pressure is
absorbed and discharged by the rupture of the panel.
7.8.12
Adequate ventilation is also required to ensure that
no excessive flammable vapour accumulates to dangerous level arising from the
venting process. Explosion venting should be taken as a complementary measure
and prior consideration is to eliminate the possibility of occurrence of
explosion by adopting other safety measures.
Precaution during dispensing and decanting
7.8.13
Dispensing and decanting of flammable liquids should
be carried out in such a way to avoid liquid spill and release of vapour. Workers should be aware of the potential
hazards and assess the risk before dispensing and decanting. The use of enclosed transfer system is
preferable and in circumstances where the enclosed system is inapplicable,
appropriate containers that are designed to minimize spill and release of
vapour, and to prevent fire should be used. The
containers should possess the following safety features:
l
metal or heavy-duty plastic construction. Plastic
containers need to be compatible with the liquid that they are intended to
contain;
l
the containers should incorporate anti-static features
so that any metal components in the transfer system would not build up
electrostatic charge.
l
pouring and/or filling apertures sealed with
self-closing spring loaded caps; and fitted with flame arresters;
l hoses or other aids when dispensing into small openings;
l
carrying handles for containers with a capacity
approximately greater than 2.5 litres as a general guideline.
7.8.14
Open-topped cans and buckets are not suitable
for handling or storing
flammable liquids. Drums for
flammable liquids should have secure closures that can withstand the expected
handling conditions without leaking. Drums
with large removable ends are not normally suitable for flammable liquids. Open-ended drums or receptacles with
fitting lids or covers may be adequate for viscous liquids such as paints,
provided the container is not easily tipped over. Drums and cans should always be opened easily and closed
securely but not by punching holes in the cap or on the drum wall.
7.8.15
Transfer of flammable liquid to containers from bulk
quantity should preferably be conducted in open air or designated area with adequate ventilation to reduce hazard in case of any spillage. Spill trays or other
means to contain spillages should be provided where decanting or dispensing is
carried out. Containers should be
properly earthed.
Precaution during handling
and storage
7.8.16
Incompatible chemicals such as flammable liquids,
oxidising agents and combustible materials, etc. should be clearly labelled and
stored separately from one another away from direct sunlight and other heating
sources and preferably, in a cool, well-ventilated store constructed of
fire-resisting materials.
7.8.17
Small quantities of flammable liquids
should be stored in a fire-resisting cupboard
or bin with clear marking
outside the container. Larger quantities of flammable
liquids should be stored in a separate fire-resisting room constructed in accordance with the requirements of the Dangerous
Goods Ordinance (Chapter 295).
7.8.18
Spillages should be avoided wherever possible by the
provision and use of non-spill containers.
7.8.19
When spillages or leakages do occur they should be dealt with quickly
in the way as recommended by the supplier.
8
Emergency Preparedness
8.1
Overview
8.1.1
Emergency preparedness is vital to provide quick and
effective response to industrial incidents that may result in injuries, loss of
life and damages of property. During
the use of flammable liquids, emergency situations mainly arise from chemical
spillages, and on some occasions from fire and explosion.
8.1.2
In regard to chemical safety and health in the use of
flammable liquid, the employer or management should:
(a)
identify and list out all possible emergency
situations in the workplace;
(b)
assess the effects
and impacts of the emergency
situations;
(c)
develop and implement
an emergency response
plan, which may include procedures to handle minor
leaks and spills, and an evacuation plan ;
(d)
provide and maintain
emergency equipment and other necessary resources; and
(e)
ensure that staff
are familiarised with the arrangements in case of emergencies by providing procedural
instructions and employee training and organising drills.
8.1.3
Appropriate first aid facilities and adequate numbers
of trained first- aiders as required by the Occupational Safety and Health Regulation should be
provided.
8.1.4
The MSDS in respect of handling accidental release of flammable liquids and disposal of waste
should be consulted.
8.2 Emergency response
plan
8.2.1
An emergency response plan should be established for
handling various foreseeable emergency situations in the workplace. It should provide the following:
(a)
assignment of responsibilities;
(b)
alarm systems;
(c)
emergency response procedures; and
(d)
schedule for emergency
drills.
8.2.2
Assignment of responsibilities -- It is extremely
important that all employees understand their own roles during any emergency
situations as assigned in the overall safety
plan. In particular, the head of the emergency response
team should be charged with the following duties:
(a)
assessing the emergency situation and taking necessary
actions;
(b)
overseeing the implementation of the emergency response plan;
(c)
organising regular drills;
and
(d)
ensuring all emergency
equipment is well maintained.
8.2.3
Emergency response procedures -- Emergency response
procedures are operating instructions for employees to follow in case of emergency
situations. Appropriate procedures should be established for each type of emergency situations and cover the
following:
(a)
reporting, declaring and clearing off emergencies;
(b)
handling of emergency
situations;
(c)
evacuation; and
(d)
deployment of employees to perform critical operations
before they evacuate.
8.2.4
The emergency response plan and related information
should be documented and communicated to all employees: evacuation routes,
names and locations of first aid team members, locations of safety equipment,
telephone numbers of key personnel and emergency services. The documents should be kept or posted in prominent
places in the workplace for easy access by all staff.
8.2.5
Handling of spillages of hazardous chemicals and other
emergencies should be included in the chemical safety programme.
8.3 Emergency equipment
8.3.1
Appropriate emergency equipment
should include but not limited
to:
(a)
fire alarm;
(b)
fire-fighting equipment, such as fire hoses, fire extinguishers
and fire blankets;
(c)
emergency lights and backup for fume extraction in case of power failure;
(d)
emergency showers and eyewashes;
(e)
first aid facilities, such as first
aid kit; and
(f)
absorbent material for cleanup of minor chemical
spills.
8.3.2
All emergency equipment should be properly
maintained and regularly inspected for proper
performance. Expired items should be
replaced. Locations of emergency equipment in the workplace should be made
known to all staff.
9
Hazard Communication
9.1
Overview
9.1.1
Under the
Occupational Safety and Health Ordinance, employers are obliged to provide
such information as is necessary to ensure the safety and health of their
employees at work.
9.1.2
The information is indispensable in the identification
of potential hazards related to the use and handling
of workplace chemicals during risk assessment and preparation of emergency response
plans.
9.2
Sources of hazard
information
9.2.1
Limited but essential hazard information can be found
on the label of the container of the substances, whereas detailed information
can be obtained from the suppliers (chemical manufacturers, importers or
distributors) of the chemicals. Other
information sources include chemicals catalogues, chemistry journals, chemical
handbooks and online databases.
9.3
Means of hazard communication
9.3.1
Typical means of hazard communication include labels,
MSDS, standard operating procedures and employee training. Employers may also find placards, notices
and signboards useful for their workplaces.
Labels
9.3.2
Labelling each container containing hazardous substance is the most direct means of hazard
communication. The label
should include the following information:
(a)
identity of the substance -- chemical name(s) or
common name(s);
(b)
hazard classification and symbol(s);
(c)
indication of the particular risks
inherent in the substance; and
(d)
indication of the required safety precautions.
9.3.3
If it is not reasonably practicable to put full
information on a container, the container should at least be labelled with the
identity of the chemical and the hazard group(s) and symbol(s). Other required information can be given in
an information sheet placed in the close vicinity. Statutory requirements for labelling of dangerous substances are
prescribed in the
Factories and Industrial Undertakings (Dangerous Substances) Regulations.
Material Safety Data Sheet (MSDS)
9.3.4
An MSDS provides important source of information about
a specific chemical used in the processing work, especially when the chemical
is used for the first time. The
information includes safe handling and storage of the chemical, first-aid
procedures, potential effects of contact and measures to take in the event of a
spill or leak. ISO 11014-1 recommends a standard format
for the MSDS,
which contains the following
sixteen sections or headings of information:
(i)
product and company
identification;
(ii)
composition/information on ingredients;
(iii)
hazards identification;
(iv)
first-aid measures;
(v)
fire-fighting measures;
(vi)
accidental release measures;
(vii) handling and storage;
(viii) exposure controls/personal protection;
(ix)
physical and chemical
properties;
(x)
stability and reactivity;
(xi)
toxicological information;
(xii) ecological information;
(xiii) disposal considerations;
(xiv) transport information;
(xv) regulatory information; and
(xvi) other information.
Standard operating procedures (SOP)
9.3.5
Hazard information can also be communicated via SOP, which
refer to a set of systematic step-by-step written procedures to be followed
for completing a process or operation.
The SOP should describe the tasks to be performed, data to be recorded, operating
conditions to be applied with associated safety and
health precautions.
9.3.6
The inclusion of appropriate hazard information in SOP
relies very much on how thorough and thoughtful the risk assessment is
undertaken, so as to effectively eliminate or control the risks in the entire
process.
10
Information,
Instruction and Training
10.1 Overview
10.1.1
After assessing the risks in the workplace and
adopting appropriate preventive measures, employers should make sure that their
employees fully understand the risks at work, and that the work practices can
help them perform their jobs safely. To
achieve this, employees should be provided with adequate safety information,
instruction and training.
10.2 Information and instruction
10.2.1
Employees should be informed of the following:
(a)
safety information about the flammable liquids
regarding the risks that they could probably be exposed to, including the
nature of hazards, exposure standards, possible routes of entry
into the body and risks to health;
(b)
correct labelling of flammable liquids and the
significance of label details;
(c)
content and significance of MSDS;
(d)
measures to reduce the risks of exposure to flammable
liquids, including practice of personal hygiene;
(e)
safe work procedures on the use, handling, storage, transportation, cleaning up and disposal of flammable
liquids;
(f)
information on the safe handling
of plant and equipment;
(g)
emergency response procedures, including locating and
using emergency equipment and facilities for first aid, decontamination and
fire-fighting;
(h)
procedures for reporting faults and incidents,
including spills; and
(i)
proper selection, use and maintenance of PPE.
10.2.2 Information and instruction should
be provided to employees by:
(a)
SOP, safety manual, and emergency procedures being
located in prominent locations in the workplace easily accessible by employees;
(b)
others such as notice, poster and video show arousing
the safety awareness of everyone on handling flammable liquids and relating
processes.
10.3
Employee training
10.3.1
Employees should be informed of the hazards
arising from the use of flammable liquids and the need to eliminate ignition
and heat sources from work area. Training on proper handling and storage of
flammable liquids should be provided. The
training should also include emergency procedures for dealing with incident. Periodic refresh training should be
arranged. Content of the training programme should include those information
and instruction aspects as detailed in paragraph 10.2.1.
10.3.2
Training helps employees to acquire the necessary
skills and knowledge that enable them to follow safe working procedures, take
appropriate control measures, use appropriate personal protective equipment and
follow emergency procedures. Training
should also enable employees to participate in decision-making relevant to
workplace safety and health.
10.3.3
Employers should ensure that all persons involving in
use of flammable liquids, including workers, supervisors, store staff,
emergency personnel and safety and health representatives are adequately
trained.
10.3.4
Training should be an ongoing process so that
employees can learn about the new developments of workplace safety and continue
to improve their relevant knowledge and skills. Refresher training is useful
and should be provided, especially to employees returning from an extended leave of absence or when there are changes of
work procedures that may render previous training obsolete.
10.3.5
The training programme
should be reviewed
periodically to make sure
that employees are gaining the skills and knowledge they need. Employers should
also ensure that their employees, after undergoing
appropriate training, understand what they have been taught.
10.3.6
Employers should keep the training record, which
should include at least the following:
(a)
names of employees receiving training, and dates of attendance;
(b)
outline of the course content;
and
(c)
names and credentials of trainers.
Appendix I
Fire/explosion Data of Some
Flammable Liquids Used in Workplace
|
|
|
|
|
Boiling point (℃) |
|
|
|
|||||
|
|
|||||
|
Acetaldehyde |
-38 |
185 |
4 – 60 |
20.2 |
|
|
Acetic Acid |
39 |
427 |
5.4 – 16 |
118 |
|
|
Acetic Anhydride |
49 |
316 |
2.7 – 10.3 |
139 |
|
|
Acetone |
-18 |
465 |
2.2 – 13 |
56 |
|
|
n-Amyl Acetate |
25 |
360 |
1.1 – 7.5 |
149 |
|
|
iso-Amyl Acetate |
25 |
360 |
1 – 7.5 |
142 |
|
|
sec-Amyl acetate |
32 |
380 |
1 – 7.5 |
121 |
|
|
n-Amyl Alcohol |
33 |
300 |
1.2 – 10.5 |
138 |
|
|
iso-Amyl Alcohol |
45 |
350 |
1.2 – 9 |
132 |
|
|
sec-n-Amyl alcohol |
34 |
360 |
1.2 – 9 |
116 |
|
|
Benzaldehyde |
62 |
190 |
1.4 – 13.5 |
179 |
|
|
Benzene |
-11 |
498 |
1.2 – 8 |
80 |
|
|
Benzyl Chloride |
67 |
585 |
1.1 – 14 |
179 |
|
|
n-Butyl Acetate |
22 |
420 |
1.2 – 7.6 |
126 |
|
|
Butyl Alcohol |
29 |
345 |
1.4 – 11.3 |
117 |
|
|
Carbon Disulphide |
-30 |
90 |
1 – 50 |
46 |
|
|
Chlorobenzene |
27 |
590 |
1.3 – 11 |
132 |
|
|
|
|
|
|
152 |
|
|
Cyclohexane |
-18 |
260 |
1.3 – 8.4 |
81 |
|
|
|
|
|
Boiling point (℃) |
|
|
|
|||||
|
|
|||||
|
Cyclohexanone |
44 |
420 |
1.1 – 9.4 |
156 |
|
|
1, 1-Dichloroethane |
-6 |
458 |
5.6 – 11.4 |
57 |
|
|
Diethyl Ketone |
13¬ |
452 |
1.6 – 3 |
102 |
|
|
1,4-Dioxan |
12 |
180 |
2 – 22.5 |
101 |
|
|
Ethyl Acetate |
-4 |
427 |
2.2 – 11.5 |
77 |
|
|
Ethyl Alcohol |
13 |
363 |
3.3 – 19 |
79 |
|
|
Ethylbenzene |
18 |
432 |
1 – 6.7 |
136 |
|
|
n-Heptane |
-4 |
285 |
1.1 – 6.7 |
98 |
|
|
n-Hexane |
-22 |
225 |
1.1 – 7.5 |
69 |
|
|
Isoprene |
-54 |
220 |
1.5 – 8.9 |
34 |
|
|
Kerosene |
37 – 65 |
220 |
0.7 – 5 |
150 – 300 |
|
|
Methyl Acetate |
-13 |
455 |
3.1 – 16 |
57 |
|
|
Methyl Acrylate |
-2.8 |
468 |
2.8 – 25 |
80.5 |
|
|
Methyl Alcohol |
12 |
464 |
5.5 – 44 |
65 |
|
|
Methyl
Ethyl Ketone (MEK) |
-9 |
505 |
1.8 – 11.5 |
80 |
|
|
Methyl
Isobutyl Ketone |
14 |
460 |
1.4 – 7.5 |
117 – 118 |
|
|
Methyl Methacrylate |
10¬ |
421 |
1.7 – 12.5 |
100.5 |
|
|
Octane |
13 |
220 |
1.0 – 6.5 |
126 |
|
|
n-Propanol |
15 |
371 |
2.1 – 13.5 |
97 |
|
|
Isopropyl alcohol
(IPA) |
11.7 |
456 |
2 – 12 |
83 |
|
|
n-Propyl Acetate |
14 |
450 |
2 – 8 |
101.6 |
|
|
Isopropyl acetate |
2 |
460 |
1.8 – 7.8 |
89 |
|
|
Styrene |
31 |
490 |
0.9 – 6.8 |
145 |
|
|
|
|
|
Boiling point (℃) |
|
|
|
|||||
|
|
|||||
|
Thinner |
4.5 |
300 |
Dependent on
product formulation |
98 – 105 |
|
|
Toluene |
4 |
480 |
1.1 – 7.1 |
111 |
|
|
Turpentine |
30 – 46 |
220 – 255 |
0.8 – 6 |
149 – 180 |
|
|
m-Xylene |
27 |
527 |
1.1 – 7.0 |
139 |
|
|
o-Xylene |
32 |
463 |
0.9 – 6.7 |
144 |
|
|
p-Xylene |
27 |
528 |
1.1 – 7.0 |
138 |
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