General purpose: prevent exposure to toxic, irritating, or noxious chemical vapors and gases. A face velocity of 100 feet per minute (fpm) provides efficient vapor capture while reducing hood turbulence.

• Baffles -- keep the airflow uniform across the hood opening, thus eliminating dead spots and optimizing capture efficiency.• Sash --Airflow across the hood can be adjusted by sash height to the point where capture of contaminants is maximized.• Airfoil -- Preventing the creation of turbulent eddies that can carry vapors out of the hood. The space below the bottom airfoil provides source of room air for the hood to exhaust when the sash is fully closed.• Exhaust plenum -- An important engineering feature, the exhaust plenum helps to distribute airflow evenly across the hood face.• Face -- The imaginary plane running between the bottom of the sash to the work surface. Hood face velocity is measured across this plane.

The Safety of work with the laboratory fume hoods

ReferencesUniversity of Washington; http://www.ehs.washington.edu/fsofumehoods/fume.shtmPrinceton University; http://web.princeton.edu/sites/ehs/labsafetymanual/sec6b.htmWaterloo University; http://www.safetyoffice.uwaterloo.ca/hse/fume_hoods/fume_hoods.htmColgate University; http://www.colgate.edu/offices/administrative/financeandadministration/environmentalhealthandsafetyoffice /chemicalhygienelaboratorysafety/chemicalfumehoods

Good

Safe Hood Operating Procedure

Work with the hood sash partially or completely closed.

Move work at least six inches inside the face of the fume hood. This minimizes the effect of cross-drafts and eddies created by the hood operator or by occupants walking by the hood. Also, keeping windows and doors closed will control cross-drafts.

BestBad

Safe Hood Operating Procedure

Avoid overcrowding the fume hood work areas. Chemicals and equipment not in use should be removed from the hood to a proper storage cabinet. Large bulky equipment used in the hood will cause eddies that can be reduced by making sure there is a 1-2 inch air space on all sides including the bottom. Avoid using equipment that blocks the hood sash from closing.

Constant volume hood – the volume of air exhausted is constant, regardless of sash height.Proper positioning of the sash is vital to maintaining the optimum face velocity (100 or 125 fpm).Too high: lowers face velocity, allowing contaminants to escape from the hoodToo low: results in very high face velocity, excessive turbulence and loss of containment

Confirm that the hood is operational: switch ‘on’, airflow gauge or ‘flow check ribbon’ hood test data and optimum sash height - yellow label affixed to the hood face

Maintain operations at least 6" inside the hood face Lower sash to optimum height: maximized airflow without turbulence (17” in accordance to the

rules in Colgate University) Keep head out of hood and Keep hands out as much as possible Keep hood storage to an absolute minimum (Do not use your fume hood as a storage area) Minimize foot traffic around the chemical hood Use extreme caution with ignition Connect all electrical devices outside of the hood to avoid sparks which may ignite a flammable or

explosive chemical Replace hood components prior to use When fume hood is not in use, keep sash closed and ensure that all materials are in sealed

containers Prepare a plan of action in case of an emergency, especially when using extremely hazardous

chemicals or acids, and a flammable or explosive chemical

Safe Hood Operating Procedure

the science lab safety equipment, including:Safety ShowerEye WashFire BlanketsFire ExtinguishersFire ExitsTelephoneFirst Aid KitHand-washing sinkMaster gas shut-offMaster electricity shut-offBiohazardous waste containerSharps containersBroken glass containersRoutine garbage containersChemical disposal containers

SAFETY EQUIPMENT In case of an emergency, you should know the location and proper use of all the safety equipment provided in the laboratory.

Always immediately inform the staff of any accident.

Laboratory fires

A study of one hundred significant laboratory fires by the National Fire Protection Association provides some interesting facts:

71% of the fires originated in the laboratories; 56% of the laboratory fires originated between 6 PM and 6 AM; 67% of the fires were caused by: electrical equipment (wire and appliances) 21% misuse of flammable liquids 20% explosions 13% gas 7% spontaneous ignition 6%

Which kind of extinguisher should I use?

The National Fire Protection Association classifies fires into five general categories (U.S.):

* Class A fires are ordinary materials like burning paper, lumber, cardboard, plastics etc.

* Class B fires involve flammable or combustible liquids such as gasoline, kerosene, and common organic solvents used in the laboratory.

* Class C fires involve energized electrical equipment, such as appliances, switches, panel boxes, power tools, hot plates and stirrers. Water can be a dangerous extinguishing medium for class C fires because of the risk of electrical shock unless a specialized water mist extinguisher is used. (DO NOT USE WATER)

* Class D fires involve combustible metals, such as magnesium, titanium, potassium and sodium as well as pyrophoric organometallic reagents such as alkyllithiums, Grignards and diethylzinc. These materials burn at high temperatures and will react violently with water, air, and/or other chemicals. Handle with care!! (DO NOT USE WATER)

(*Class K fires are kitchen fires)

Class A fires are those fueled by materials that, when they burn, leave a residue in the form of ash, such as paper, wood, cloth, rubber, and certain plastics.

Class B fires involve flammable liquids and gasses, such as gasoline, paint thinner, kitchen grease, propane, and acetylene.

Class C fires are those that involve energized electrical wiring or equipment (motors, computers, panel boxes)

Class D fires involve exotic metals, such as magnesium, sodium, titanium.

Which kind of extinguisher should I use?

Which kind of extinguisher should I use?

http://safety.eas.ualberta.ca/node/46

Extinguisher type Class of Fire Examples of Fire type Distinguising Features

Water Aordinary materials, paper, wood, plastics,cardboard

etc...

not recommended for lab or electrical fires; water-logged debris

Water mist AHospital environments,

books,clean-rooms, MRI and NMR rooms

Misting nozzle provide safety from electrical shock and reduce scattering of burning material

Dry chemical(powder)

BC - Na or K carbonateABC - ammonium

phosphate

A, B, and C Combustible liquids, laboratory solvents etc... Overlaying powder reduces re-ignition

Dry metal powderCopper agent

NaCl agentD

Metal and lithium alloy fires (Cu)

Mg, Na, K, Uranium and Al fires (NaCl)

Powder cling to vertical and 3-D surfaces (Cu).Cakes and forms crust over surface - excludes air,

dissipates heat (NaCl).

Dry sand D Electrical etc... Smother embers

Carbon dioxideCO2

B and C

Flammable solvents, electrically charged

equipment and appliances, tools, switches etc...

Leaves no harmful residue, but may re-ignite with class A fires

Halotron 1 B and C

As for carbon dioxide. Ideal for computer rooms, clean

rooms, electronics environments etc...

No thermal or static shock,non-conducting, discharges as "clean agent" liquid and has high visibility

HydrofluorocarbonsHFC - 236fa and fe - 36TM B and C To replace Halotron types. "Cleanguard" zero-ozone depleting

Summary of Fire extinguishers

http://delloyd.50megs.com/hazard/fire.html

Extinguisher type Class of Fire Examples of Fire type Distinguising Features

Water Aordinary materials, paper, wood, plastics,cardboard

etc...

not recommended for lab or electrical fires; water-logged debris

Water mist AHospital environments,

books,clean-rooms, MRI and NMR rooms

Misting nozzle provide safety from electrical shock and reduce scattering of burning material

Dry chemical(powder)

BC - Na or K carbonateABC - ammonium

phosphate

A, B, and C Combustible liquids, laboratory solvents etc... Overlaying powder reduces re-ignition

Dry metal powderCopper agent

NaCl agentD

Metal and lithium alloy fires (Cu)

Mg, Na, K, Uranium and Al fires (NaCl)

Powder cling to vertical and 3-D surfaces (Cu).Cakes and forms crust over surface - excludes air,

dissipates heat (NaCl).

Dry sand D Electrical etc... Smother embers

Carbon dioxideCO2

B and C

Flammable solvents, electrically charged

equipment and appliances, tools, switches etc...

Leaves no harmful residue, but may re-ignite with class A fires

Halotron 1 B and C

As for carbon dioxide. Ideal for computer rooms, clean

rooms, electronics environments etc...

No thermal or static shock,non-conducting, discharges as "clean agent" liquid and has high visibility

HydrofluorocarbonsHFC - 236fa and fe - 36TM B and C To replace Halotron types. "Cleanguard" zero-ozone depleting

Summary of Fire extinguishers

http://delloyd.50megs.com/hazard/fire.html

*Carbon dioxide fire extinguishers are suitable for many of the potential fire hazards in the general chemistry laboratories.

(1) Aim nozzleat base of fire.

(2) Pull outlocking key. (3) Squeeze

handles.

How to use a Fire extinguisher In the event of a fire, evacuate the area, close all doors, call for help, and sound local alarms. If you attempt to extinguish it, keep your back to an exit from the laboratory, do not allow yourself to become trapped or cornered in the lab.

In case of a clothing fire, a fire blanket should be used.

Remove the fire blanket from its container using the straps.

Wrap it around the person to completely cover the person and smother the fire.

How to use a Fire blanket

Clarkson University 268-6400Emergency Number (after working hours) 268-6439Campus Safety 268-6666Fire Dept 9-265-3311Hospital 9-265-3300/3304/5720Police 9-265-2121/2122Rescue Squad 911(Numbers are located near the each lab exit door)

How to respond to an Emergency