Teledyne 4220 installation and operation guide Table D-1 Hazardous Gases

4220 Flow Meter

Appendix D General Safety Procedures

D.3 Hazardous Gases

number of harmful vapors. They, too, are sensed by smell and explosimeter tests if they get into the public sewer. Such occur- rences are rare.

“The attempt to instill a sense of urgency about real hazards is diluted if a man is told to give attention to a long list of things that in fact are irrelevant.

“Be very careful to avoid high H2S concentrations, flammable atmospheres, and hazards of physical injuries. Remember that much H2S may be released by the stirring up of sludge in the bottom of a structure. Obey your senses in respect to irritating gases, such as chlorine (unconsciousness comes suddenly from breathing too much). Be cautious about strange odors. Do not determine percent oxygen in the air. There is a danger that the result will influence a man's thinking about the seriousness of the real hazards. Most important, use ample ventilation, and do not enter a potentially hazardous structure except in a good safety harness with two men at the top who can lift you out.”

The following table contains information on the properties of hazardous gases.

Table D-1 Hazardous Gases

			Specific		Max	Max. Safe	Explosive		Likely		Simplest and
			Gravity				Range (% by		Location	Most
	Chemical	Common		Physiological	Safe 60	8 Hour					Cheapest
Gas			or Vapor				vol. in air)		of	Common
	Formula	Properties		Effect	Min. Exposure	Exposure					Safe Method
			Density				Limits		Highest	Sources
					ppm	ppm					of Testing
			Air =1				lower/upper		Concentration
Ammonia	NH3	Irritant and	0.60	Causes throat	300	85	16	25	Near top.	Sewers,	Detectable
		poisonous. Col-		and	to				Concentrates	chemical	odor at low
		orless		eye irritation at	500				in closed up-	feed	concentrations
		with characteris-		0.05%, cough-					per spaces	rooms.
		tic		ing
		odor.		at 0.17%. Short
				exposure at
				0.5%
				to 1% fatal.
Benzene	C6H6	Irritant, colorless	2.77	Slight symp-	3,000	25	1.3	7.1	At bottom.	Industrial	Combustible
		anesthetic		toms	to					wastes,	gas indicator
				after several	5,000					varnish,
				hours						solvents.
				exposure at
				0.16% to 0.32%.
				2% rapidly
				fatal.
Carbon	CS2	Nearly odorless	2.64	Very poison-	—	15	1.3	44.0	At bottom	An insecti-	Combustible
Bisulfide		when pure, color-		ous,						cide	gas indicator
		less, anesthetic.		irritating, vom-
		Poisonous.		iting,
				convulsions,
				psychic distur-
				bance.

D-6