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9 comments
Power-User

Join Date: Mar 2008
Location: Mumbai
Posts: 240
Good Answers: 2

H2S level

04/26/2009 1:52 PM

Dear Frnds

I am aware that H2S Con Above 10 PPM is harmful, okay nowhere i work h2s comes all of a Sudden with Con rising to 30-60 Ppm , portable h2s monitor detects that and v vacate place

but this con is lethal for how days / Hours , so that we can start work safely in that area( i mean till what time does our body requires to get back normal).

In one day how much H2S we Can inhale ?

Also I like to know what are the effects of H2S in our body, long run

Regards

Jose John

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Guru
Engineering Fields - Environmental Engineering - New Member APIX Pilot Plant Design Project - Member - New Member

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#1

Re: H2S level

04/26/2009 10:59 PM

Too much H2S is lethal .

"but this con is lethal for how days / Hours , so that we can start work safely in that area( i mean till what time does our body requires to get back normal)."

You may need to be warded for observation, as the H2S may react with water and oxygen in your lungs to form sulfuric acid . H2S also causes systemic damage to the body and nervous system .

"In one day how much H2S we Can inhale?"

As little as possible . I mean, really, considering WHAT it smells like, why on earth would anyone want to inhale it at all ?!

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Anonymous Poster
#8
In reply to #1

Re: H2S level

04/27/2009 12:59 PM

Some people have to make a living!

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Guru
Engineering Fields - Environmental Engineering - New Member APIX Pilot Plant Design Project - Member - New Member

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#9
In reply to #8

Re: H2S level

04/28/2009 1:52 AM

Wear a respirator when dealing with such things !!!!

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Commentator

Join Date: May 2008
Location: Tweed Valley, Australia
Posts: 95
Good Answers: 7
#2

Re: H2S level

04/26/2009 11:03 PM

There are a few facts you need to know about Hydrogen Sulphide (H2S) gas.

The Maximun allowable level in the atmosphere is 10ppm. Over 20ppm and up to 150ppm causes irritation of the eyes and mucous membranes. At a level of 500ppm for 30 minutes exposure you will be feeling nauseus, have a bad headache, be dizzy and disoriented. At 600ppm you may die inside of 30 minutes due to upper respiratory system paralysis.

Although 10ppm is the recommended maximium allowable level, most humans will start to detect H2S at less than 1ppm. At 10ppm it will be highly offensive to most. However prolonged exposure to low levels of H2S paralyses your sense of smell so may not 'smell' higher dose rates.

H2S as such does not 'accumulate' in the body, but it does combine with moisture (water) to form sulphuric acid, which can accumulate and make life quite uncomfortable.

Workplace where H2S is known to be prevalent MUST be protected by use of a gas detector and should also have sufficient positive velocity ventilation to ensure that diluted gas never exceeds 10ppm.

My advice to you is to get a fan and dilute the gas as much as possible where people are going to be working.

Regards,

Pete.

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Anonymous Poster
#4
In reply to #2

Re: H2S level

04/26/2009 11:41 PM

It is also important to note that you will NEVER smell large concentrations, because immediately upon contact, your sense of smell will be destroyed. Below, I have listed most of the info I have on it. I work around it all the time, and when you have a small leak, it's best to be expecting a large leak soon. Someone qualified needs to get in supplied air and find the problem quick. Pressure does some wild things to seals and fittings when you least expect it.

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Anonymous Poster
#3

Re: H2S level

04/26/2009 11:36 PM

NIOSH Pocket Guide to Chemical Hazards

Hydrogen sulfide

CAS 7783-06-4

H

2S

RTECS MX1225000

Synonyms & Trade Names
Hydrosulfuric acid, Sewer gas, Sulfuretted hydrogen

DOT ID & Guide
1053 117

Exposure Limits

NIOSH REL: C 10 ppm (15 mg/m

3) [10-minute]

OSHA PEL†: C 20 ppm 50 ppm [10-minute maximum peak]

IDLH 100 ppm See: 7783064

Conversion 1 ppm = 1.40 mg/m3

Physical Description
Colorless gas with a strong odor of rotten eggs. [Note: Sense of smell becomes rapidly fatigued & can NOT be relied upon to warn of the continuous presence of H2S. Shipped as a liquefied compressed gas.]

MW: 34.1BP: -77°FFRZ: -122°FSol: 0.4%
VP: 17.6 atmIP: 10.46 eVRGasD: 1.19
Fl.P: NA (Gas)UEL: 44.0%LEL: 4.0%
Flammable Gas

Incompatibilities & Reactivities
Strong oxidizers, strong nitric acid, metals

Measurement Methods
NIOSH 6013; OSHA ID141
See: NMAM or OSHA Methods

Personal Protection & Sanitation (See protection)
Skin: Frostbite
Eyes: Frostbite
Wash skin: No recommendation
Remove: When wet (flammable)
Change: No recommendation
Provide: Frostbite wash

First Aid (See procedures)
Eye: Frostbite
Skin: Frostbite
Breathing: Respiratory support

Important additional information about respirator selection

Respirator Recommendations NIOSH
Up to 100 ppm:
(APF = 25) Any powered, air-purifying respirator with cartridge(s) providing protection against the compound of concern
(APF = 50) Any air-purifying, full-facepiece respirator (gas mask) with a chin-style, front- or back-mounted canister providing protection against the compound of concern
(APF = 10) Any supplied-air respirator*
(APF = 50) Any self-contained breathing apparatus with a full facepiece
Emergency or planned entry into unknown concentrations or IDLH conditions:
(APF = 10,000) Any self-contained breathing apparatus that has a full facepiece and is operated in a pressure-demand or other positive-pressure mode
(APF = 10,000) Any supplied-air respirator that has a full facepiece and is operated in a pressure-demand or other positive-pressure mode in combination with an auxiliary self-contained positive-pressure breathing apparatus
Escape:
(APF = 50) Any air-purifying, full-facepiece respirator (gas mask) with a chin-style, front- or back-mounted canister providing protection against the compound of concern/Any appropriate escape-type, self-contained breathing apparatus

Exposure Routes inhalation, skin and/or eye contact

Symptoms Irritation eyes, respiratory system; apnea, coma, convulsions; conjunctivitis, eye pain, lacrimation (discharge of tears), photophobia (abnormal visual intolerance to light), corneal vesiculation; dizziness, headache, lassitude (weakness, exhaustion), irritability, insomnia; gastrointestinal disturbance; liquid: frostbite

Target Organs Eyes, respiratory system, central nervous system

See

International Chemical Safety Cards

HYDROGEN SULFIDE

ICSC: 0165


Sulfur hydride
H

2S
Molecular mass: 34.1
(cylinder)
ICSC # 0165
CAS # 7783-06-4
RTECS # MX1225000
UN # 1053
EC # 016-001-00-4
October 04, 2002 Peer reviewed

TYPES OF HAZARD/ EXPOSURE

ACUTE HAZARDS/ SYMPTOMS

PREVENTION

FIRST AID/
FIRE FIGHTING

FIRE

Extremely flammable.NO open flames, NO sparks, and NO smoking.Shut off supply; if not possible and no risk to surroundings, let the fire burn itself out; in other cases extinguish with water spray, powder, carbon dioxide.

EXPLOSION

Gas/air mixtures are explosive.Closed system, ventilation, explosion-proof electrical equipment and lighting. Prevent build-up of electrostatic charges (e.g., by grounding) if in liquid state. Do NOT use compressed air for filling, discharging, or handling.In case of fire: keep cylinder cool by spraying with water.

EXPOSURE

AVOID ALL CONTACT!IN ALL CASES CONSULT A DOCTOR!

•INHALATION

Headache. Dizziness. Cough. Sore throat. Nausea. Laboured breathing. Unconsciousness. Symptoms may be delayed (see Notes).Ventilation, local exhaust, or breathing protection.Fresh air, rest. Half-upright position. Artificial respiration may be needed. No mouth-to-mouth artificial respiration. Refer for medical attention.

•SKIN

ON CONTACT WITH LIQUID: FROSTBITE.Cold-insulating gloves.ON FROSTBITE: rinse with plenty of water, do NOT remove clothes. Refer for medical attention.

•EYES

Redness. Pain. Severe deep burns.Safety goggles, or eye protection in combination with breathing protection.First rinse with plenty of water for several minutes (remove contact lenses if easily possible), then take to a doctor.

•INGESTION

Do not eat, drink, or smoke during work.

SPILLAGE DISPOSAL

STORAGE

PACKAGING & LABELLING

Evacuate danger area! Consult an expert! Remove all ignition sources. Ventilation. Remove gas with fine water spray. Personal protection: gas-tight chemical protection suit including self-contained breathing apparatus.Fireproof. Separated from strong oxidants. Cool. Keep in a well-ventilated room. Install continous monitoring system with alarm.
F+ symbol
T+ symbol
N symbol
R: 12-26-50
S: 1/2-9-16-36-38-45-61
UN Hazard Class: 2.3
UN Subsidiary Risks: 2.1

SEE IMPORTANT INFORMATION ON BACK

ICSC: 0165

Prepared in the context of cooperation between the International Programme on Chemical Safety & the Commission of the European Communities (C) IPCS CEC 1994. No modifications to the International version have been made except to add the OSHA PELs, NIOSH RELs and NIOSH IDLH values.

International Chemical Safety Cards

HYDROGEN SULFIDE

ICSC: 0165

I

M

P

O

R

T

A

N

T


D

A

T

A

PHYSICAL STATE; APPEARANCE:
COLOURLESS COMPRESSED LIQUEFIED GAS , WITH CHARACTERISTIC ODOUR OF ROTTEN EGGS.

PHYSICAL DANGERS:
The gas is heavier than air and may travel along the ground; distant ignition possible. As a result of flow, agitation, etc., electrostatic charges can be generated.

CHEMICAL DANGERS:
Heating may cause violent combustion or explosion. The substance decomposes on burning producing toxic gases (sulfur oxides). Reacts violently with strong oxidants, causing fire and explosion hazard. Attacks many metals and some plastics.

OCCUPATIONAL EXPOSURE LIMITS:
TLV: 10 ppm as TWA; 15 ppm as STEL; (ACGIH 2004).
MAK: 10 ppm, 14 mg/m³;
Peak limitation category: II(2); Pregnancy risk group: IIc;
(DFG 2004).
OSHA PEL: C 20 ppm 50 ppm 10-minute maximum peak
NIOSH REL: C 10 ppm (15 mg/m3) 10-minute
NIOSH IDLH: 100 ppm

ROUTES OF EXPOSURE:
The substance can be absorbed into the body by inhalation.

INHALATION RISK:
A harmful concentration of this gas in the air will be reached very quickly on loss of containment.

EFFECTS OF SHORT-TERM EXPOSURE:
The substance is irritating to the eyes and the respiratory tract . The substance may cause effects on the central nervous system . Exposure may result in unconsciousness. Exposure may result in death. Inhalation of gas may cause lung oedema (see Notes). The effects may be delayed. Medical observation is indicated. Rapid evaporation of the liquid may cause frostbite.

EFFECTS OF LONG-TERM OR REPEATED EXPOSURE:

PHYSICAL
PROPERTIES

Boiling point: -60°C
Melting point: -85°C
Solubility in water, g/100 ml at 20°C: 0.5
Relative vapour density (air = 1): 1.19
Flash point: Flammable Gas
Auto-ignition temperature: 260°C
Explosive limits, vol% in air: 4.3-46

ENVIRONMENTAL
DATA

The substance is very toxic to aquatic organisms.

N O T E S

The symptoms of lung oedema often do not become manifest until a few hours have passed and they are aggravated by physical effort. Rest and medical observation are therefore essential. Specific treatment is necessary in case of poisoning with this substance; the appropriate means with instructions must be available. The substance blocks the sense of smell. The odour warning when the exposure limit value is exceeded is insufficient. Card has been partly updated in October 2004. See sections Occupational Exposure Limits, EU classification, Emergency Response.
Transport Emergency Card: TEC (R)-20G2TF or 20S1053

NFPA Code: H4; F4; R0;

ADDITIONAL INFORMATION

ICSC: 0165

HYDROGEN SULFIDE

(C) IPCS, CEC, 1994

IMPORTANT LEGAL NOTICE:

Neither NIOSH, the CEC or the IPCS nor any person acting on behalf of NIOSH, the CEC or the IPCS is responsible for the use which might be made of this information. This card contains the collective views of the IPCS Peer Review Committee and may not reflect in all cases all the detailed requirements included in national legislation on the subject. The user should verify compliance of the cards with the relevant legislation in the country of use. The only modifications made to produce the U.S. version is inclusion of the OSHA PELs, NIOSH RELs and NIOSH IDLH values.
Specific Medical Tests or Examinations Published in the Literature
for OSHA-Regulated Substances

Hydrogen sulfide

CAS No: 7783-06-4

NOTE:
(1) Efficacy of Medical Tests has not been evaluated.
(2) NIOSH references include diagnostic, screening, and other tests.
(3) OSHA mandated medical tests, if any, are provided in BOLD on a yellow background.
(4) This HTML page was created from DHHS (NIOSH) Publication No. 2005-11O. December 2004.
(5) If a medical test/examination contains multiple references, each is listed separately.

Editor(s) / Author(s)

Specific Medical Test(s)
or Examination(s)

Reference(s)


Baselt RC.

Whole Blood (chemical/metabolite)

Biological Monitoring Methods for Industrial Chemicals. 3rd Edition. Chemical Toxicology Institute,1997.


Linch AL.

Whole Blood (chemical/metabolite)
  • Carboxyhemoglobin


Biological Monitoring for Industrial Chemical Exposure Control. CRC Press. 1974.

Baselt RC.

Blood Plasma

Biological Monitoring Methods for Industrial Chemicals. 3rd Edition. Chemical Toxicology Institute,1997.


US DHHS PHS CDC NIOSH and US DOL OSHA.

Chest X-ray

NIOSH/OSHA Occupational Health Guidelines for Chemical Hazards DHHS (NIOSH)

Pub No. 81-123; 88-118; Suppls. I-IV. 1981–1995.


Proctor NH, Hughes JP.

Chest X-ray

Chemical Hazards of the Workplace. JB Lippincott Company. 1978.


US DHHS PHS CDC NIOSH and US DOL OSHA.

Pulmonary Function Tests
  • Forced Vital Capacity
  • Forced Expiratory Volume (1 sec)


NIOSH/OSHA Occupational Health Guidelines for Chemical Hazards DHHS (NIOSH)

Pub No. 81-123; 88-118; Suppls. I-IV. 1981–1995.


Proctor NH, Hughes JP.

Pulmonary Function Tests
  • Forced Vital Capacity
  • Forced Expiratory Volume (1 sec)


Chemical Hazards of the Workplace. JB Lippincott Company. 1978.

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Guru
United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

Join Date: Jan 2007
Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain - possibly to become "South Scotland" or "Non-Caledonia" from September 2016. Kettle's on.
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Good Answers: 579
#5

Re: H2S level

04/27/2009 3:50 AM

<...h2s comes all of a Sudden with Con rising to 30-60 Ppm...>

That office seems awfully familiar....

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Commentator
India - Member - Naveen Menon Engineering Fields - Instrumentation Engineering - Naveen Menon

Join Date: Oct 2007
Location: India
Posts: 93
Good Answers: 2
#6

Re: H2S level

04/27/2009 7:47 AM

Guest has done the right job of putting up the MSDS in the thread.

I feel that you really require to learn regarding H2S and also inform the dangers regarding the same to your collegues , because ignorance with Chemicals can be dangerous.

it would be good to install a Personal area monitor with A beacon with horn so that you would be able to inform all in the area that you need to vacate and also you know when the horn dies that its ok to enter.

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Anonymous Poster
#7

Re: H2S level

04/27/2009 12:54 PM

If I remember correctly for every 15minutes you work in or around H2S con @ 10ppm or below requires 10minutes of fresh air (20.9 oxygen). Any con @ 11ppm and up breathing air is suggested. H2S is a very dangerous gas that should not be taken lightly. It's short term effects at small con normally go away after in fresh air for a while, long term affects at continued exposure can lead to upper resportory problems and central nervous system. Be safe and good luck!!

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