CONTENTS OF FIRST AID KIT/ BOX - WHAT'S INSIDE YOUR FIRST AID BOX

FIRST AID KIT/ BOX CONTENT BASIC INFORMATION
What Should Be The Content of your First Aid Emergency Kit or Box?

Impact on first-aid provision if risks are significant. First aiders may need to be appointed if risks are significant. This will involve a number of factors which must be considered, including:

➤ training for fi rst aiders
➤ additional first-aid equipment and the contents of the first-aid box
➤ siting of first-aid equipment to meet the various demands in the premises. For example, provision of equipment in each building or on several floors. There needs to be first-aid provision at all times during working hours
➤ informing local medical services of the site and its risks
➤ any special arrangements that may be needed with the local emergency services.

If employees travel away from the site the employer needs to consider:
➤ issuing personal fi rst-aid kits and providing training
➤ issuing mobile phones to employees
➤ making arrangements with employers on other sites. Although there are no legal responsibilities for nonemployees, the HSE strongly recommends that they are included in any first-aid provision.

Contents of the first-aid box
There is no standard list of items to put in a first-aid box. It depends on what the employer assesses the needs to be. Where there is no special risk in the workplace, a minimum stock of first-aid items is tabulated below.

Tablets or medicines should not be kept in the first-aid box. Table is a suggested contents list only; equivalent but different items will be considered acceptable.

PHOTOIONIZATION METERS BASIC INFORMATION AND TUTORIALS

What Are Photoionization Meters?

Description and Applications.
Ionization is based upon making a gas conductive by the creation of electrically charged atoms, molecules, or electrons and the collection of these charged particles under the influence of an applied electric field.

The photoionization analyzer is a screening instrument used to measure a wide variety of organic and some inorganic compounds.

It is also useful as a leak detector. The limit of detection for most contaminants is approximately 0.1 ppm.

Calibration. The procedure for calibration involves applying the
calibration gas (typically 100 ppm isobutylene) to the instrument
and checking the reading.

Special Considerations.
The specificity of the instrument depends on the sensitivity of the detector to the substance being measured, the number of interfering compounds present, and the concentration of the substance being measured relative to any interference.

Many models now have built-in correction or correlation factors. After calibrating the unit on isobutylene, select the gas to be measured.

The instrument will automatically correct for the relative sensitivity of the gas selected. Some instruments are listed by an NRTL for hazardous locations.

Check the operating manual for specific conditions.

Maintenance.
Keeping these instruments in top operating shape means charging the battery, cleaning the ultraviolet lamp window, light source and replacing the dust filter. The exterior of the instrument can be wiped clean with a damp cloth and mild detergent if necessary.

Keep the cloth away from the sample inlet, however, and do not attempt to clean while the instrument is connected to line power.

TOP 10 HAZARDOUS TASKS IN ELECTRICAL WORKS

Typical hazardous tasks in electrical work

The following tasks are some examples of possible exposure to energized conductors:

a) Measuring, testing, and probing electrical system components;

b) Working near battery banks;

c) Opening electrical equipment enclosure doors or removing covers;

d) Inserting or pulling fuses;

e) Drilling, or otherwise penetrating, earth, walls, or ßoors;

f) Pulling conductors in raceways, cable trays, or enclosures;

g) Lifting leads or applying jumpers in control circuits;

h) Installing or removing temporary grounds;

i) Operating switches or circuit breakers;

j) Working inside electronic and communications equipment enclosures.

SAFETY SWITCHES FOR ELECTRONIC EQUIPMENT BASIC INFORMATION

Fuses are typically installed in safety switches. Separately mounted fused safety switches are typically categorized as general-duty and heavy-duty types.

The general-duty type safety switch is rated at 240 V maximum and is typically used in residential and light commercial and industrial applications. The heavy-duty type safety switch is rated at 600 V maximum and is typically used in commercial and industrial applications.

Safety switches can typically be ordered with neutral assemblies and equipment grounding assemblies. There is currently no listing for safety switches that are to be used specifically with nonlinear loads.

It is recommended that the manufacturer be contacted to determine if oversized neutral assemblies can be installed in safety switches serving nonlinear electronic load equipment without voiding any listing requirements. In addition, the manufacturer should be contacted to determine if an isolated equipment grounding bus can be installed in the safety switch enclosure for those applications that require this grounding configuration.

Whenever fuses are utilized, there is a risk of a single-phasing condition if one fuse on a three phase system blows. Safety switches are generally not stored energy devices, and may not contain auxiliary functions such as undervoltage release or shunt trip attachments that help protect against a single-phasing condition.

This is an important consideration because some three phase electronic load equipment may be susceptible to damage if a single-phase condition persists. Other devices may need to be installed to provide proper single-phasing protection.

Blown fuse indicators
Recommended practice is to use blown fuse indicators for the quick and safe determination of the source of power outage affecting downstream electronic load equipment. Some safety switches and fused circuit breakers contain indicating devices located on the front enclosure that indicate a blown fuse condition. Some fuses contain an indicator light, providing visual indication that a fuse is blown.

Interrupting ratings
Interrupting ratings of new fuses or existing fuses should be evaluated to determine if proper interrupting ratings are applied. Interrupting ratings need to be reevaluated if there are any changes to the power system, such as installing K-factor transformers.

These transformers are typically specified or manufactured with a low impedance (%Z) resulting in a higher available short-circuit current on the secondary. This condition can be a problem especially where low interrupting capacity fuses, such as Class H fuses, are installed (Class H fuses have an interrupting rating of only 10 000 A).

STANDBY GENERATOR SYSTEM FOR ELECTRONIC EQUIPMENT BASIC INFORMATION AND TUTORIALS

Incompatibility issues regarding emergency standby generator systems and downstream electronic load equipment are gaining more recognition in modern power systems. UPS systems and electronic load equipment can be very susceptible to voltage waveform distortion and frequency variations.

The distortion of the voltage waveform is primarily a function of the magnitude and harmonic content of the load current and the impedance of the upstream electrical distribution system. Standby generator systems generally have a much higher impedance than the utility system.

Therefore, the voltage waveform distortion typically increases when loads are fed by standby generator power. One of the most common incompatibility situation is with generator systems and downstream UPS systems.

These situations can range from problems with the UPS inverter trying to synchronize to the static bypass circuit to the UPS input failing to accept the input voltage and thus causing the UPS system to go to battery power.

In this latter condition, the voltage distortion typically improves when the load is fed from battery power (the load is now on battery and not acting on the impedance of the generator system) and the UPS input accepts the line voltage. Once again, voltage distortion can increase when the loads are powered via the UPS system, and the UPS

a) Isochronous electronic governor to regulate frequency. These governors typically maintain frequency regulation within 0.25% of the setting, as opposed to approximately 3% for mechanical governors.

b) Permanent magnet excitation system or filtering means to isolate the voltage regulator
power circuit from the distorted waveform.

c) Generators with a 2/3 pitch stator winding design to minimize third harmonic waveform distortion.

d) Low subtransient reactance to minimize voltage waveform distortion. cycles back and forth on battery power. Recommended practice is to provide the standby generator manufacturer with information on the type, rating, and characteristics of the electronic load equipment.

Many generator manufacturers and UPS manufacturers have guidelines for sizing emergency generators when supplying UPS systems. This rating will typically depend on the type and size of the UPS system.

In general, the standby generators should have the following characteristics to minimize adverse interactions when supplying nonlinear loads.

ANALYSES OF HARMONIC CURRENTS AND VOLTAGE OF ELECTRONIC EQUIPMENT BASIC INFORMATION AND TUTORIALS

Refer to IEEE Std 519-1992 for a general discussion of harmonic currents. Recommended practice is for all power distribution systems intended for use with electronic load equipment comply with IEEE Std 519-1992 and IEEE Std 399-1997 guidelines. Calculation or estimation of load harmonic profiles is a necessary requirement when installing power factor correction equipment, selecting K-factor rated transformers or derating existing conventional transformers.

Improvements in power factor may be desired for financial reasons (to lower utility costs associated with power factor penalties) or operational reasons (to lower system losses, increase system reserve capacity, or improve voltage conditions). Extreme caution should be used when applying capacitors.

The manner in which they are applied can cause resonance conditions that can magnify harmonic levels and cause excessive voltage distortion. Power factor correction equipment may be applied directly at or close to the facility service entrance, or as close as practicable to the load equipment.

The location of the power factor equipment will depend on economic reasons, as well as operational and design considerations.

Thorough analysis of distribution system characteristics and load characteristics should be made prior to applying power factor correction capacitors to determine what effect harmonic currents will have on the system, and to determine proper harmonic mitigation techniques. Refer to IEEE Std 141-1993 for further discussion on application of power factor correction capacitors.

It is recommended practice to measure and record the harmonic profile of load currents at the transformers serving the load. When the harmonic profiles of individual loads at downstream locations are measured, there is a tendency to calculate a higher than necessary K-factor.

This is also the case in new installations where the current harmonic profile is estimated from typical
individual pieces of electronic load equipment based upon experience or data supplied by the OEM. Due to cancellation, the combined contribution to K-factor of several loads is always less than the sum of individual loads.

This reduction may be substantial when there is a large number and a diversity of nonlinear load types. Figure below shows an example of how harmonic levels vary in a typical electrical distribution system. Note that the level of harmonic current distortion decreases from the individual electronic load equipment to the branch circuit panelboards, through delta-wye stepdown transformers, and upstream to the power source.

However, when loads are removed from the electrical distribution system, the cancellation benefit produced by these loads is also removed. In many cases, this will not be a problem for a transformer that is conservatively loaded or is K-factor rated. It may be a problem if the load or K-factor rating is marginal.

Cancellation results when harmonics produced by different loads are phase-shifted relative to each other. Impedance in branch circuit wiring, as well as isolation transformers or series inductors and shunt capacitors that may be incorporated in the loads, shift harmonic currents.

A delta-wye transformer serving single-phase nonlinear loads randomly distributed among the three phases will trap the balanced triplen load harmonics in the primary winding. This may substantially reduce the triplen harmonic currents and the related current and voltage distortion that would otherwise appear on the primary side.

It is difficult to predict a harmonic diversity factor without modeling the nonlinear loads and the electrical distribution system. Computer programs and methods that allow modeling and simulation are becoming available.

With more experience, these computer analysis tools are expected to provide diversity factors for typical loads in industrial and commercial power systems. For new installations, where such diversity factors are not available, recommended practice is to monitor the load current distortion and diversity relative to the load mix in a comparable facility.

PROJECT RISK CONTROL - HIERARCHY OF RISK CONTROLS BASIC INFORMATION AND TUTORIALS

When assessing the adequacy of existing controls or introducing new controls, a hierarchy of risk controls should be considered. The Management of Health and Safety at Work Regulations 1999 Schedule 1 specifies the general principles of prevention which are set out in the European Council Directive.

These principles are:
1. avoiding risks
2. evaluating the risks which cannot be avoided
3. combating the risks at source
4. adapting the work to the individual, especially as regards the design of the workplace, the choice
of work equipment and the choice of working and production methods, with a view, in particular, to alleviating monotonous work and work at a predetermined work-rate and to reducing their effects on health
5. adapting to technical progress
6. replacing the dangerous by the non-dangerous or the less dangerous
7. developing a coherent overall prevention policy which covers technology, organization of work, working conditions, social relationships and the influence of factors relating to the working environment
8. giving collective protective measures priority over individual protective measures and
9. giving appropriate instruction to employees.

These principles are not exactly a hierarchy but must be considered alongside the usual hierarchy of risk control which is as follows:

S elimination
S substitution
S engineering controls (e.g. isolation, insulation and
ventilation)
S reduced or limited time exposure
S good housekeeping
S safe systems of work
S training and information
S personal protective equipment
S welfare
S monitoring and supervision
S reviews.

TRANSFORMER TERMS GLOSSARY BASIC INFORMATION AND TUTORIALS

The following technical terms apply to transformers.

BIL: An abbreviation for basic impulse level, a dielectric strength test. Transformer BIL is determined by applying a high-frequency square-wave voltage with a steep leading edge between the windings and between the windings and ground.

The BIL rating provides the maximum input kV rating that a transformer can withstand without causing insulation breakdown. The transformer must also be protected against natural or man-made electrical surges. The NEMA standard BIL rating is 10 kV.

Exciting current: In transformers, the current in amperes required for excitation. This current consists of two components: (1) real in the form of losses (no load watts) and (2) reactive power in kvar. Exciting current varies inversely with kVA rating from approximately 10 percent at 1 kVA to as low as 0.5 percent at 750 kVA.

Eddy-current losses: Contiguous energy losses caused when a varying magnetic flux sets up undesired eddy currents circulating in a ferromagnetic transformer core.

Hysteresis losses: Continuous energy losses in a ferromagnetic transformer core when it is taken through the complete magnetization cycle at the input frequency.

Insulating transformer: A term synonymous with isolating transformer, to describe the insulation or isolation between the primary and secondary windings. The only transformers that are not insulating or isolating are autotransformers.

Insulation system temperature: The maximum temperature in degrees Celsius at the hottest point in the winding.

Isolating transformer: See insulating transformer.

Shielded-winding transformer: A transformer with a conductive metal shield between the primary and secondary windings to attenuate transient noise.

Taps: Connections made to transformer windings other than at its terminals. They are provided on the input side of some high-voltage transformers to correct for high or low voltages so that the secondary terminals can deliver their full rated output voltages.

Temperature rise: The incremental temperature rise of the windings and insulation above the ambient
temperature.

Transformer impedance: The current-limiting characteristic of a transformer expressed as a percentage. It is used in determining the interrupting capacity of a circuit breaker or fuse that will protect the transformer primary.

Transformer voltage regulation: The difference between the no-load and full-load voltages expressed as a percentage. A transformer that delivers 200 V at no load and 190 V at full load has a regulation of 5 percent.

ELECTROCUTION AND ELECTRICAL FATALITIES BASIC INFORMATION

The term electrocution refers to an electrical event with electrical current exposure that results in death. The implication is that the current flow has caused an electrical shock with subsequent death.

“Electrical accident fatality” is a general use phrase seen in news reports meaning either electrocution, or death resulting at the time of the electrical accident. This phrase may include fatalities associated shock or other forms of energy released at the time of the electrical accident, in particular those causing physical changes including burns, blast effects, and radiation damage.

“Electrical injury mortality” is a medical statistics phrase which suggests that persons who were injured in an electrical accident lived long enough to receive medical care for their injuries, but the medical care was not followed by survival.

It’s important to appreciate that an electrical event can produce a fatality or injury even when there is no electrical current flow to the victim or electrical shock. This might be the situation, for example, when a victim is caught in an electrical ignition fire, explosion, or blast.

In this type of scenario, the “root cause” of the accident is electrical, but the mechanism of death or injury is from thermal, acoustic, radiation, or blast exposure related to electrothermal chemical (ETC) combustion.

Another way employees can be killed or injured after an electrical event is that they are surprised by an energized source, either through a spark, like a static “zap” to exposed skin, or through a noise, like a sharp “gunshot” type sound close to the head.

The surprise can lead to an unintended body movement which might be characterized as a “startle response.” If the startle occurs at the top of a ladder or scaffold, the direct mechanism of death or injury can be through a fall.

If the startle occurs in proximity to other energized equipment that is moving, the direct mechanism of death or injury can be with a body part being caught in or by the moving equipment.

Fatal and non-fatal electrical incidents share three characteristics:

1. The unintentional exposure of employees to electrical energy;
2. Compliance failure in at least one aspect of electrical design, installation, policies, procedures, practices, or personal protection; and
3. Energy transfer to exposed employees in some combination of electrical, thermal, radiation, acoustic (pressure), mechanical, light, kinetic, or potential energy.

What is the difference between fatal and non-fatal electrical incidents? The answer depends in part on whether the question is asked hypothetically, like in a “what if ” planning scenario; or whether the question is asked retrospectively after a traumatic accident has occurred.

Hypothetically, based on human physical and biological characteristics, we know that a fatal electrical event transfers a greater amount of energy to its victim than a non-fatal situation. This knowledge about the fatal risk of energy transfer underlies the use of equipment designs (for example, required doors, specified space clearances, venting systems on equipment to discharge combustion products, “umbilical corded” controls, infrared monitoring ports for doors closed heat monitoring) and barrier protection (such as PPE, including leather gloves, flash suits, safety glasses, face shields, long sticks, extended handles, and flame resistant clothing).

By reducing the amount of possible energy transfer during an unintentional electrical exposure, strategies including equipment design and barrier protection can increase the likelihood of survival after an electrical incident.

Retrospectively, if two people are present in an electrical incident when one dies and the other survives, the difference in survival may come down to nuances in the victims’ innate individual differences and their spatial and temporal relationship to the electrical hazard at the time of the energy release, transformation, and transfer. Medical and legal privacy protections tend to reduce accessibility to accident details, so systematic information is lacking about how various scenarios unfold.

Generally, there is a lethal exposure “dose” for different forms of energy that can result in death. When multiple forms of energy are involved in an electrical event, multiple lethal or sublethal doses of energy may flow from the event, transformed from the electrical hazard source, and transferred to nearby employees may result in highly variable damage to the body.

EFFECT OF CURRENT and ITS DURATION TO THE HUMAN BODY DURING ELECTRIC SHOCK

WHAT KILLS A PERSON? CURRENT OR VOLTAGE?

To answer the question, we need to put things in context. That means, there is no absolute. Current kills, but it needs to be present for a certain period of time.

The amount of energy delivered to the body is directly proportional to the length of time that the current flows; consequently, the degree of trauma is also directly proportional to the duration of the current. Three examples illustrate this concept:

1. Current flow through body tissues delivers energy in the form of heat. The magnitude of energy may be approximated by:

J = I²Rt

where J = energy, joules
I = current, amperes
R = resistance of the current path through the body, ohms
t = time of current flow, seconds

If sufficient heat is delivered, tissue burning and/or organ shutdown can occur. Note that the amount of heat that is delivered is directly proportional to the duration of the current (t).

2. Some portion of the externally caused current flow will tend to follow the current paths used by the body’s central nervous system. Since the external current is much larger than the normal current flow, damage can occur to the nervous system.

Note that nervous system damage can be fatal even with relatively short durations of current; however, increased duration heightens the chance that damage will occur.

3. Generally, a longer duration of current through the heart is more likely to cause ventricular fibrillation. Fibrillation seems to occur when the externally applied electric field overlaps with the body’s cardiac cycle. The likelihood of this event increases with time.

Also, we need to understand how much current is significant.

The magnitude of the current that flows through the body obeys Ohm’s law, that is,

I = E/R

where I = current magnitude, amperes (A)
E = applied voltage, volts (V)
R = resistance of path through which current flows, ohms (Ω)

Parts of the Body. 
Current flow affects the various bodily organs in different manners. For example, the heart can be caused to fibrillate with as little as 75 mA.

The diaphragm and the breathing system can be paralyzed, which possibly may be fatal without outside intervention, with less than 30 mA of current flow. The specific responses of the various body parts to current flow are covered in later sections.

Nominal Human Response to Current Magnitudes

EMERGENCY LIGHTING SYSTEM DESIGN CONSIDERATIONS CODES AND STANDARDS

Emergency lighting is required when the normal lighting is extinguished, which can occur for any of three reasons:

1. General power failure
2. Failure of the building’s electrical system
3. Interruption of current flow to a lighting unit, even as a result of inadvertent or accidental operation of a switch or circuit disconnect.

As a result of the third reason, sensors must be installed at the most localized level—that is, at the lighting fixture (voltage sensor) or in the lighted space (photocell sensor).

Codes and Standards
Because emergency lighting is a safety-related item, it is covered by various codes, several of which may
have jurisdiction. In addition, there are widely accepted technical society and industry standards whose recommendations normally exceed the minimal required by codes.

1. Life Safety Code (NFPA 101, 2009). This code defines the locations within specific types of structures requiring emergency lighting and specifies the level and duration of the lighting.

2. National Electrical Code (NFPA 70, 2008). This code deals with system arrangements for emergency light (and power) circuits, including egress and exit lighting. It discusses power sources and system design.

3. Standard for Health Care Facilities (NFPA 99, 2005). This code deals with special emergency light and power arrangements for these facilities.

4. OSHA regulations. These are primarily safety oriented and, in the area of emergency lighting, discuss primarily exit and egress lighting requirements.

5. Industry standards. These include the publications of the IESNA and the IEEE, in particular Recommended Practice for Emergency and Standby Power Systems for Industrial and Commercial Applications (IEEE Standard 446-1995).

Because codes and standards are constantly being revised and updated, the designer for an actual project must determine which codes have jurisdiction, obtain current editions, and design to fulfill their requirements. The following material provides general information and focuses on good practice but is not intended to take the place of applicable construction and safety codes.