CONTROL OF HAZARDOUS ENERGY

Types of Energy To Be Controlled Kinetic – Energy of motion Potential – Energy of position Electrical – From generated

electricity, battery or static source Thermal – result of mechanical

work, radiation, chemical reaction or electrical resistance

7 Basic Lockout Steps

1) Prepare for Shutdown2) Shut Down3) Isolate4) Apply Locks5) Verify Isolation6) Control Stored Energy7) Prepare for Startup

What is Isolation?

• Meaning – Prevention of the normal flow of energy.• Blocking in the case of gravitational

energy• Disconnection in the case of electrical

energy.• Ether blocking or disconnection in the

case of the flow of fluid through a pipe.

What Does “Apply Locks” Include?

• Apply Locks = Securing the Point of Control• Preventing unauthorized persons from

reactivating the flow of energy.• Use of locks, tags or posting of

qualified person(s).

What Does “Control Stored Energy” Mean?

• Cause Energy To Be Reduced to Levels Tolerable by Humans.

Mechanical Motion

• Can be linear translation or rotation

• Allow motion to stop before work. • Can be turned off

Potential Energy

• Potential Energy – Pressures, springs, and gravity.

• Can be controlled, but can not be turned off

Electrical Energy

• Electrical power can be turned off• Static Electricity cannot be turned

off, but can be dissipated

Thermal Energy

• High or low temperature• Result of:

• Mechanical work• Radiation• Chemical reaction• Electrical Resistance

• Can’t be turned off – must be controlled or dissipated

Chemical Reaction

• Take heat in or give off heat• Controlled by:

• Elimination, dissipation or control of chemically-reactive materials

• Control reaction so energy release doesn’t harm humans.

Example –Control Potential Energy by Removing Spring From Car

• Control gravity by blocking the car• Control spring energy by blocking or

dissipation of energy.

Example – Mixing Drum Rotating Blades Repair

• Switch off electrical source• Lock out and/or disconnect

mechanical linkages• Tag switch (and mechanical

linkages?)

Forms of Hazardous Potential Energy – As You Come Up With Examples Of These At Your Site, Raise Your Hand And Let’s Discuss How You Control Each One!

• Hydraulic or pneumatic pressure• Vacuum systems• Compressed or extended springs• Gravity energy• Energy of motion such as a flywheel• Stored electrical energy – Battery, Capacitor• Thermal Energy due to residual heat or low

temperatures• Residual chemicals in pipe which may cause

thermal or pressure buildup.

Controlling Hazardous Energy Sources by De-energizing

• Thorough Inspection and Listing Of All Potentially Hazardous Energy Sources• Include adjacent equipment

Controlling Hazardous Energy Sources by De-energizing

• Stored or residual energy that constitutes a personnel hazard shall be isolated, blocked or dissipated.• Isolate, block or dissipate at points of

control that cannot, with reasonable effort, be overridden or by-passed•Isolation or blocking is adequate when

unplanned event would not reactivate the flow of energy

Applying Locks or Securing The Point of Control• Use of physical means such that re-

energizing requires special equipment routinely available only to the person who applied the control or.

• Post warning at the point(s) of control saying why controlled, date, person(s) responsible for control and for work to be done. Limit access to control point(s) or

• Post Qualified personnel at the point of control with specific responsibility of protecting against unauthorized actuation (used primarily for short duration work..

Verify Effectiveness of Controls• Ensure that all hazardous energy has

been isolated, blocked or dissipated in areas where personnel will perform required tasks.

• Verification may need to be continuous if there is a potential for re-accumulation of energy.

Controlling Hazards With Energy Present• Identify hazardous energy sources

including residual energy sources• Document procedures and assign

responsibility and accountability for controlling personnel hazards

• Qualify personnel who perform maintenance by education, experience and/or training and certification

Example - Controlling Mechanical Motion

• Remove segments of operating mechanical linkages such as dismantling push rods, removing belts, removing flywheels.

• Secure Point of Control• Tag linkages and place in locked cabinet• Attach warning tags where linkages removed

& restrict access• Post person to protect against unauthorized

reinstallation of linkages

Example - Controlling Mechanical Motion

• Use blocking devices• Secure point of control by:

• Chain and lock or use metal pins driven or welded in place

• Attach warning tags and restrict access• Post person(s) to protect against

unauthorized removal of blocking devices

Example - Controlling Mechanical Motion

• Remove Power or energy by disconnecting main electrical source or closing hydraulic or pneumatic valves, bleed.• Padlock in the “off” position (check

for alternate sources of power)

Example - Controlling Mechanical Motion

• Close hydraulic or pneumatic valves, bleed.• Disconnect pneumatic and hydraulic

lines and tag or attach warning tags at control points and restrict access to trained personnel or post a person

• Check for residual pneumatic and hydraulic energy.

Example - Controlling Electrical Energy• Place the main electrical

disconnect switch in the “off” position• Secure by padlock, clip and padlock or

bar and padlock (check for alternate sources of power and programmed controllers) or

• Attach warning tag and restrict access to trained personnel or

• Post a person

Example - Control of Electrical Energy• Remove segments of electrical circuit,

such as printed circuit modules.• Tag module and lock in cabinet away from

control center; Tag control center door or• Attach a warning tag at the module location

and restrict access or• Post person at control center

Example - Control of Thermal Energy (Steam)

• Close valves and maintain an open bleed.• Chain and padlock valve or use blind

flanges or slip blinds or• Attach warning tags to the valves and

restrict access or• Station person at valve locations

Example - Control of Pressure Energy

• Close valves and maintain open vent to relieve• Secure, block, blind flange, slip blind,

or valve with locking device or• Attach warning tags and restrict

access • Station a person at the valves

Example - Control of Gravity Energy

• Block in place using metal or wood blocks under the mechanism or pin the linkages in position where gravity won’t cause the mechanism to fall.• Energy could be dissipated by lowering to floor

or other secure surface or• Secure, block or pin with a locking device or• Attach warning tags to blocks, linkages and pins

and restrict access or• Station a person to restrict access

Example - Controlling Spring Energy• Block in safe position by pinning or

clamping• Dissipate energy by release or dismantling

of the mechanism or• Secure pin or clamp in place with locking

device or• Attach warning tags to pins and clamps and

restrict access or• Station person at control point to protect

against pin or clamp removal