gas cylinder safety valve free sample

Pressure regulators reduce the high pressures of the stored gas in the cylinder to lower pressures that can be safely used in an operating system. Proper regulator selection is critical for both safety and effectiveness of operating systems. Regulators are designed to control pressure; they do not measure or control flow, unless equipped with devices such as a flow meter specifically designed for such purposes.

Regulator connections to cylinder valves must be completely free of dirt, dust, oil, and grease. "Crack" the valve slowly (by opening the valve slightly and then reclosing it) before attaching the regulator in order to blow out dust and debris from the opening. Note: Cylinders containing highly toxic gases should not be "cracked".

Regulators are attached to the cylinder, or manifold, at the inlet connection. This connection should be tested for leaks with a non-petroleum based product. Note that many soaps contain petroleum! The connection is marked with a Compressed Gas Association (CGA) number and will be left-hand or right-hand threaded to match the nut or fitting. This prevents a piece of incompatible gas equipment from being connected to the wrong gas supply.

Opening a Regulator - Stand on the valve side of the cylinder at arms length so you do not have to reach in front of the regulator face. Turn your head away from the regulator and open the valve, turning counter clockwise, to blow out dust and debris, and then reclose the valve.

Changing a Regulator - Close the valve and drain the regulator by backing out the adjusting screw. Disconnect the regulator, making sure not to touch the nut and gland areas. Connect the regulator to the new cylinder.

Closing a Regulator - Turn the valve clockwise to close the valve. Drain the regulator by turning (opening) the adjusting crew to release any gas. Reclose the adjusting screw.

Recommendation: To provide easier access and additional safety, purchase wall-mounted regulators which connect to the supply cylinder by hose. This will reduce the handling of the regulator and reduce the likelihood of damage.

Diaphragm Valve - This valve uses a two piece stem separated by non-perforated diaphragms. These diaphragms prevent leakage along the valve stem. The lower part of the stem is encased in a spring, which forces the stem away from the seat whent eh valve is opened. The upper stem is threaded into the diaphragm retainer nut. When the handwheel is rotated to the closed position, the upper stem pushes on the diaphragms, which deflect downward, forcing the lower stem against the valve seat. Advantages of this type of valve are that they provide superior leak integrity and have no threads or lubricants in the gas stream to generate particles or contaminants. This type of valve is required for mos

Compressed gas cylinders shall have a pressure relief device installed to prevent the rupture of a normally pressurized cylinder when inadvertently exposed to fire of high temperatures. There are four basic types of pressure relief devices:

Rupture Disk Devices - A flat disk typically made of metal that is designed to burst at a predetermined pressure to permit the release of gas. The pressure rating of the disk is typically stamped onto the face of the device. Examples of gases using this type of device include compressed air, argon, helium, nitrogen, and oxygen.

Fusible Plug Devices - A plug made of fusible metal designed to yield or melt at low temperatures (usually 165 or 212 degrees F). The temperature rating of the fusible metal is stamped onto the face of the device. An examples of a gas that uses this type of device is acetylene.

Combination Ruture Disks/Fusible Plug Devices - A rupture disk backed by a fusible plug. In the event of a fire, the fusible metal melts and cylinder overpressure is relieved by the bursting of the disk. The burst pressure of the disk and the melting point of the plug will be marked with the ratings. Medical grade gas cylinders typically have this type of pressure relief device.

Pressure Relief Valves - A spring-loaded valve opens when the cylinder pressure exceeds the pressure setting of the spring to discharge contents. Once the cylinder pressure decreases to the valve"s pressure setting, the valve will normally reseat without leakage.

We will explain compressed gas cylinder Safety guidelines in the term of identification, storage, handling, hazards, precaution and use of industrial compressed gas cylinders.

Argon, oxygen, acetylene, gases are compressed under high pressure and can be stored inside the cylinder for easy transportation and storage at working site.

Cylinders shall not be subjected to contact with direct flame, electric arc, molten metal, and other sources of heat, corrosive material or corrosive environment.

(2) Has a boiling point of 20°C or less at an absolute pressure of 101.3 kPa and that is liquefied, non-liquefied, or in solution. Gases that have no health or physical hazard properties are not considered to be compressed gases until the pressure in the packaging exceeds an absolute pressure of 280 kPa at 20°C. (Source: NFPA 55-2013, 3.3.49.1)

Cylinder :   A pressure vessel designed for absolute pressures higher than 276 kPa and having a circular cross-section. It does not include a portable tank, multiunit tank car tank, cargo tank, or tank car. (Source: NFPA 55-2013, 3.3.29)

All cylinders that are received for use on site shall be colour coded on the shoulder of the Cylinder (curved part). The colour coding is intended to identify the properties of the gas in the cylinder. A number of industrial gases have been assigned a specific colour.

Where an industrial gas does not have a specific colour, the properties of the gas shall be indicated. For gases with two properties they shall be indicated by two concentric bands.

The colour coding described only applies to the shoulder, or curved part, at the top of the cylinder and is used to identify the properties of the gas in the cylinder.

All gas cylinders are required to be labelled to indicate the contents of the cylinder. Below is an example of a typical label, with an explanation of the various items that are to be displayed. It must always be remembered that the label is the means of identifying the contents of the cylinder. The colour of the cylinder is only a guide.

A suitable area dedicated for the storage of industrial gas cylinders shall be identified and provided for the storage of industrial gas cylinders. All cylinders shall be secured in an upright position and secured with the protective caps at all times in designated cylinder storage areas. All cylinders shall be labelled, marked and stored in accordance with their contents.

A suitable location within the site shall be established for the storage of gas cylinders in accordance to the following guidelines:An area where the cylinders has minimal exposure to excessive temperature, physical damage or tempering. Compressed gas cylinders shall not be exposed to direct temperatures exceeding 38o

The storage area shall be enough to contain the projected quantity of compressed gas cylinders that may be stored on site on any given time and to allow segregation distances between incompatible gases.

2) Construction LayoutCompressed gas cylinders storage area shall be delimited with such materials as chain links, fence or open block for the full height and width of the opening. Materials used to construct the storage area shall be non-combustible.

Cylinders shall not be placed directly onto the ground where they can be exposed to conditions which could cause corrosion on the base of the cylinders. They shall be placed on a slightly elevated and smooth surface, such as concrete flooring.

All cylinders shall be stored upright and restrained from toppling (e.g. secured at two levels with chain links, ropes) and shall not be propped against a wall or bench.

Full cylinders shall be kept separated from empty cylinders and sign posted to indicate ‘Full Cylinders’, ‘Empty Cylinders’. A partition shall be established in the storage area for this purpose.

Oxygen cylinders shall be stored separately (minimum of 6 meters or twenty feet) from all other sources of combustible gas, or by means of a non-combustible barrier at least five feet (two meters) high having a fire-resistant rating of at least one-half hour.

Cylinders of the same type shall be placed together. Incompatible gases shall be either separated by a distance of 6 meters or by means of a non-combustible barrier at least 2 (two) meters high having a fire-resistant rating of at least one-half hour. All empty cylinders shall be stored separately from all other cylinders.

Cylinders shall be placed in a manner that they do not become part of an electrical circuit and shall be kept away from piping systems and layout / cutting tables that may be used for grounding electrical circuits.

4) Oil, grease and other contaminantsOil or grease ignites violently in the presence of high pressure oxygen. Cylinders and fittings shall be kept clear from all sources of contamination such as oil barrels, cranes, drive belts etc.

Suspended work platform / basket shall not be used to lift compressed gas cylinders. Lifting of cylinders by direct slinging or lifting it off its valve protection collar is strictly prohibited.

1) Care of Compressed Gas Cylinderin useLoose dirt shall be cleared by ‘sniffing’ some gas to the atmosphere (opened slowly and then closed immediately) before connecting the regulators to the valve. This shall be

The standard key issued by the supplier for the cylinders shall be used. The leverage of keys shall not be increased and badly worn keys shall be removed.

When oxygen or fuel cylinders are connected to manifolds or headers, the manifolds shall be of a proper design with one or more pressure regulators, pressure relief devices and anti-flashback arrestors.

When compressed gas is supplied to process equipment from cylinders, the proper risk assessment shall be carried out. If the result of risk assessment requires, pressure relief devices shall be installed between the equipment and regulator(s) of the cylinder(s).

A typical oxy-fuel setup is shown in below figure. Flashback arrestors and check valves shall be installed on all oxygen and acetylene cutting gear. The flashback arrestor shall be installed at the regulator end and the check valve at the cutting torch end of each hose while in operation.

The following precautions shall be taken when using hoses connected to compressed gas cylinders;Only hoses that of a good quality and fit for the task shall be purchased. Substandard quality hoses crack and leak over a certain period of time.

Hoses used to convey gases are each assigned a specific colour. All hoses used on the project shall conform with the colour coding requirements as indicated in the table below.GasColour of hose

Torches shall not be lighted up until sufficient time has elapsed for the gas in the hose to reach the working pressure and that any air in the hose has been expelled.

No one except the owner or a person approved by the owner shall refill a compressed gas cylinder. All refill operations shall take place at the supplier / manufacturer location and shall not be carried out in the project site.

The United States Department of Transportation (D.O.T.) is a department of the U.S. Federal Government which oversees all issues regarding transportation within the United States of America and U.S. Territories.  Its influence around the world is great and widely respected, but its jurisdiction and power of enforcement is limited to the USA and its territories.  As regards this paper, we will discuss the D.O.T. and its involvement surrounding sample cylinders for the hydrocarbon industry and the rules regarding the movement of these cylinders from point to point in the United States.

The most important statement to be made is that the D.O.T. and Code of Federal Regulations, Title 49 (CFR-49) is the definitive and final authority on all issues regarding the handling and transportation of sample cylinders.  Much has been written and quoted over the years and many regulations have changed over the years.  It is the sole responsibility of each company involved with sample cylinders, to have a copy of CFR-49 and to be responsible for clarification of any issues they have, by researching CFR-49 and consulting with D.O.T. representatives.  They have the final word on any questions.  D.O.T. is the enforcement agency regarding sample cylinder transportation.   The author of this paper and the company he represents do not present themselves as authorities on this matter for you or your company.  This paper is presented for the sole purpose of providing limited information and to encourage you and your company to become better informed for your specific needs and operations.

There are additional local, county and state regulations that may affect your operation.  Remember, when you leave the confines of your company property and enter any public roadway, or present a sample cylinder for transport by common carrier or other shipping means, you immediately fall under legal jurisdiction for transportation of hazardous materials.  Be informed!   In January 1988, the D. O. T. informed local law enforcement agencies that anyone who had the authority to issue a citation for vehicular movement, or any person licensed in the law enforcement business, could issue a citation for improper transportation of sample containers.  Prior to that time, the official had to be a D. O. T. officer.  Now, any officer that is familiar with the rules and regulations of cylinder transport can issue a citation.

The D.O.T. also bears the responsibility for manufacturing rules and designs for transportable sample cylinders.  CFR-49 addresses all necessary criteria for design, manufacture, testing, and marking of sample cylinders used in transporting samples in the public arena.  (Highways, ships, air, and rail.)  Cylinders, which deviate from CFR-49, must be submitted to the D.O.T. for design review, and if acceptable, are given an “Special Permit” status, assigned a special number and a document describing the details of the special permit.  In years past, this document was known as an “Exemption”, but that has changed in 2007 to “Special Permit”.  This document must accompany any “Special Permit” style of cylinder during transport.  The manufacturers of these cylinders will issue a copy of that Special Permit with each cylinder that they sell.  That document must be with the cylinder when it is being transported, and the owner of the cylinder or the person transporting the cylinder is responsible to see that it is there.

In the oil & gas industry, the most common sample cylinders are the spun-end “standard cylinder” and the constant pressure cylinder.  The standard cylinder is manufactured according to CFR-49 requirements, and the most common ones (300cc and 500cc sizes) carry the stamping “DOT-3E-1800”.  Since these cylinders are manufactured in accordance with CFR-49, they do not require a document which describes the cylinder.  The marking of “DOT-3E-1800” is sufficient.  The constant pressure cylinders do not fully follow the design criteria of CFR-49 and therefore, when approved, carry the stamping of “DOT-E-XXXXX” or DOT-SP-XXXXX from 2007 forward.  The older units in the field with DOT-E-XXXXX are grandfathered in and will not require new stamping or markings to “SP”.  The ‘X’s’ will constitute a unique number assigned by D.O.T to a given manufacturer, based on the submittals of that manufacturer to the D.O.T.  The D.O.T. will also issue a Special Permit letter with that number, describing the permit status of the style cylinder and specifically notes the areas that they approved which were outside the standard design criteria.  It is that document, which must travel with the cylinder during transport.

Be certain, that when you transport a sample of hydrocarbon products in the oil and gas industry, that you do so in a D.O.T. approved cylinder.  If not, you and your company will face penalties and fines.  This is as much your responsibility as it is your company’s.  Both of you can suffer.  These fines can reach amounts of $25,000 per cylinder, per incident.  It is a very serious matter, and must not be taken lightly.

It is the intent of D.O.T. to provide safety for all concerned during the transportation of hazardous materials.  Samples in the oil and gas industry are hazardous.  Some more so than others, but they all can be dangerous.  If you follow the rules, the hazard can be significantly reduced and almost completely eliminated.  The rules are for everyone’s protection…YOURS TOO!

As a part of this paper, a reference list is attached for frequently asked questions and the CFR-49 location for those answers.  Also, the API 14.1 standard on Gas Sampling offers additional input on labeling and handling of sample cylinders.  These references are constantly being updated and changed, and therefore it is incumbent upon you and your company to have the latest revisions to these documents so that you are in compliance with the existing law.  As we all have heard since childhood, “Ignorance is no excuse from the law!”  Your company’s legal department should be fully versed with this issue and the necessity of following the regulations.

As examples, here are some of the issues that you must be aware of, but by no means is this a comprehensive or final list of issues surrounding the handling and transportation of sample cylinders.

From the Hazardous Materials Table in CFR-49 (172.101), you must specifically and properly identify the product by name which is being transported in the container, and record that name on the bill of lading, shipping papers, or manifest for the shipment or transport of the cylinders. Also, whether it is flammable gas or flammable liquid, a poison, or other classification.

The shipping papers must be within arms reach of the driver, and that means not in the trunk with the cylinders. They should identify the owner of the cylinder by name and address.  You should have access to these papers, while your seat belt is still secured.

An emergency response number must be available and manned whenever the cylinders are in transit. The number must be manned, i.e., not an answering service or a recorder.  If that number is not manned after office hours, you need to be off the road!  If you are involved in an accident and cannot respond to questions, officials need to be able to contact someone who can tell them what to do in an emergency.  They need to know if they have a serious hazard on their hands, or simply low-pressure, flammable gas cylinders.  You would want to know, if you were in their shoes!

The cylinders must be properly packaged and protected. This includes relief valves in accordance with D.O.T. and Compressed Gas Association (CGA) rules and regulations.  The valves must be protected and the cylinders restrained from free movement, i.e., carrying cases or boxes that comply with D.O.T. packaging guidelines.

Cylinders with liquids should not be filled above 80% full to allow for expansion. Cylinders which are 100% filled with hydrocarbon liquid, should not be transported.  That is an extremely dangerous situation.

A cylinder that contains a product that meets the requirements of two or more hazardous materials must be marked and labeled for both. If you have high levels of H2S in a gas sample, then it should be affixed with Flammable Gas labels and Poison labels, with corresponding paperwork.

When transporting empty cylinders, it would be extremely helpful if they were tagged as “Empty”.  While this is not a requirement, it could save a lot of time, if the cylinders were indeed “Empty” and you were detained.  Every effort that you put forth to comply with the regulations and to show that you take this matter seriously will have a positive impact on those who enforce these laws.  They too, know the hazards that they face each day.  Cooperation with them will go a long way.

These are but a few of the important aspects in the handling and transport of sample cylinders.  Who should be aware of these rules?  1) Anyone who transports sample cylinders, 2) Anyone who offers sample cylinders for transport, 3) Anyone who prepares sample cylinders for transport, 4) Anyone who receives sample cylinders for transport.  Simply stated, if a sample cylinder is moved off of your company property on to any city, county, state, or federal roadway, airway, railway or ship, you must be in compliance with D.O.T. CFR-49 and local regulations.  Whether you are using specially designed sample cylinders, homemade sample cylinders, old compressed gas cylinders or any other conceivable method of transporting a hydrocarbon sample, if you are handling these cylinders in your vehicle or are presenting them for transport on a common carrier, you must be aware of the rules that govern the transport of these cylinders.   Failure to comply will not only jeopardize the safety of the public and your safety, but will also make you and your company liable for penalties and fines.

This paper is presented to cause awareness to the issues surrounding the transportation and handling of sample cylinders.  It is presented in a general format, and should not be used as a single source of information.  Your company must study the D.O.T. regulations and interpret them for themselves and their employees.  As these rules are constantly undergoing revision, care should be taken that your company remains up to date on the latest revision and publication.

Thank you for your letter to the Occupational Safety and Health Administration (OSHA) regarding the use, handling and storage of acetylene cylinders in general industry and construction. This letter constitutes OSHA’s interpretation only of the requirements herein, and may not be applicable to any questions not delineated in your original correspondence.

Your letter discusses concerns with the safety of compressed gas cylinders on some types of portable carts configured for “in use” or “connected for use.” Specifically you mention that cylinders, which are top heavy and therefore can be unstable (unbalanced) are commonly found poorly secured to the cart and leaves the cylinders susceptible to toppling over when used, moved, or stored. In your letter, several pictures are provided to illustrate your point (See Pictures 1, 2, and 3) of poorly secured cylinders.

As an alternative you recommend the use of a “trolley,” with an example provided in your follow up email (See picture 4), as a safer solution to ensuring protection of cylinders from toppling and creating a possible fire/explosion hazard from cylinder damage.

You reference in your letter, an updated version of the Compressed Gas Association Standard P-1-2015, 12th edition, which allows Acetylene cylinders to be positioned with the valve end up with the container axis inclined as much as 45 degrees from vertical.

Question 1: Are acetylene cylinders positioned at a 45 degree angle from vertical, as shown in picture 4, acceptable to OSHA while in use, moved, or stored?

§1910.101(b) “Compressed gases.” The in-plant handling, storage, and utilization of all compressed gases in cylinders, portable tanks, rail tankcars, or motor vehicle cargo tanks shall be in accordance with Compressed Gas Association Pamphlet P-1-1965, which is incorporated by reference as specified in §1910.6.

§1910.102(a) Cylinders. Employers must ensure that the in-plant transfer, handling, storage, and use of acetylene in cylinders comply with the provisions of CGA Pamphlet G-1-2009 (“Acetylene”) (Incorporated by reference, see § 1910.6).

§1910.253(b)(5)(iii)(A) Fuel-gas cylinders shall be placed with valve end up whenever they are in use. Liquefied gases shall be stored and shipped with the valve end up.

§1910.253(b)(5)(iii)(B) Cylinders shall be handled carefully. Rough handling, knocks, or falls are liable to damage the cylinder, valve or safety devices and cause leakage.

§1926.350(a)(9) Compressed gas cylinders shall be secured in an upright position at all times except, if necessary, for short periods of time while cylinders are actually being hoisted or carried.

§1926.350(b)(3) Fuel gas cylinders shall be placed with valve end up whenever they are in use. They shall not be placed in a location where they would be subject to open flame, hot metal, or other sources of artificial heat.

§1926.350(j) Additional rules. For additional details not covered in this subpart, applicable technical portions of American National Standards Institute, Z49.1-1967, Safety in Welding and Cutting, shall apply.

OSHA standards require the compressed gas cylinders to be in an upright position (vertical) or valve end up position. This requirement is provided to ensure the protection of and safe access to the valve while in use, during movement, or while in storage. OSHA agrees that the use of the “trolley” shown in picture 4 can provide such protection, even at a 45 degree angle from vertical. As you noted in your letter, the twelfth addition of the Compressed Gas Association Standard P-1 (Standard for Safe Handling of Compressed Gases in Containers) allows use and storage of Acetylene cylinders at a 45 degree angle from vertical. If an employer is not in compliance with the requirements of an OSHA standard but is complying with the requirements of a current consensus standard that clearly provides equal or greater employee protection, the violation of OSHA"s requirement will be treated as a de minimis condition. De minimis conditions are those having no direct or immediate relationship to safety and health and result in no citation, penalty, or requirement to abate. The use and storage of a cylinder secured to a “trolley” and reclined up to a 45 degree angle from vertical would be considered a de minimis condition, as long as all the following conditions are present:

Response: Design requirements for cylinder carts or “special trucks”, the term used in 29 CFR 1910.253(b)(5)(ii)(D), are described in the September 9, 1993, letter of interpretation to Mr. Kenneth Yotz.

“Compressed gas cylinders with the regulators installed are considered by OSHA to be ‘connected for use.’ A ‘special truck’ is a vehicle or cart used for the specific purpose of transporting the aforementioned ‘connected for use’ compressed gas cylinders in the workplace. The ‘special truck’ must be designed so that the following conditions can be met: 1) when cylinders are on the special trucks, they must be held in an erect or nearly erect position; and 2) protection of the cylinder valves and regulators must be provided.”

The conditions of the first requirement can be met for Acetylene cylinders so long as the cylinder is held in an incline of no more than 45 degrees from vertical, as stated in response 1 above. Carts that cannot meet these two requirements and are susceptible to toppling while moving cylinders or while maintained in a standing position while in use or in storage would be considered in violation of the standards and must be evaluated on a case-by-case basis. Please refer to the standards cited above which specify requirements to prevent cylinders from being knocked over while in use, being moved, or stored.

Thank you for your interest in occupational safety and health. We hope you find this information helpful. OSHA’s requirements are set by statute, standards, and regulations. Our letters of interpretation do not create new or additional requirements but rather explain these requirements and how they apply to particular circumstances. This letter constitutes OSHA’s interpretation of the requirements discussed. From time to time, such letters may be affected when the Agency updates a standard, a legal decision impacts a standard, or changes in technology affect the interpretation. To assure that you are using the correct information and guidance, please consult OSHA’s website at http://www.osha.gov. If you have any questions, please feel free to contact the Directorate of Enforcement Programs at (202) 693-2100.

Unscrew the pressure adjustment knob until the internal spring is no longer compressed, and ensure that the regulator outlet valve is closed, if one is installed. An outlet valve serves to prevent air from leaking from an open regulator into the gas lines, and is a necessity for most GC gases. An additional in-line purge valve is useful for purging air from a reconnected gas line.

Face the gas cylinder with the pressure regulator positioned on the side opposite to you, slowly open the high pressure cylinder valve, and allow the internal pressure to build up slowly in the regulator. Shut the valve immediately if an audible gas leak occurs. For gases other than air or nitrogen, use an electronic leak detector around the high-pressure fitting, the regulator gauge, and the cylinder shut-off valve to ensure there are no leaks.

Gas regulators have a finite lifetime. Most regulators will last for years with normal GC use, but each regulator should be tested upon installation and periodically after that to identify potential premature failure.

To test a regulator, first check the high-pressure gauge-it should read between 1800 and 2600 psig (12–18 mPa) for a new cylinder, depending on the type of cylinder and gas. If the gauge reading is very low, then the cylinder is not full or the gauge is defective. In this case, the best procedure is to temporarily install another suitable regulator to check the cylinder pressure. If necessary, replace the cylinder or the defective regulator. Never try to replace a gauge on a regulator or to repair any other regulator component. Only a regulator manufacturer can do that.

Next, observe the outlet pressure gauge for a few minutes, with the outlet valve closed. There should be no observable pressure increase. If the outlet pressure does go up when the pressure adjustment is fully withdrawn, then the regulator has a leak from the high-pressure side and must be returned to the manufacturer for repair or replacement. To complete checking the high-pressure side, close the cylinder valve and wait 2 min-the high-pressure gauge indication should not decrease. Any loss of high pressure with the cylinder valve closed also indicates a leak that will require repair or replacement.

Now, with the outlet valve still closed, re-open the high-pressure cylinder valve completely. Adjust the regulator outlet pressure to its operating level, which usually lies between 40 and 90 psig (275–600 kPa) for GC gases. If the outlet pressure gauge rises quickly to a high pressure, or if the gauge fails to attain the desired level despite increasing the pressure adjustment, shut off the cylinder valve and replace the regulator.

At this point an in-line purge valve can be used to bleed out any air that may have entered the regulator. Open the outlet valve slowly and pressurize the connecting tubing. The outlet pressure gauge may drop momentarily, but it should settle back quickly to its set point. Allow a few seconds to bleed gas from the purge valve, if one is used, and then close it. As a last step, I check the dynamic operation of a regulator by momentarily shutting off the cylinder valve while the regulator is delivering flow. The high-pressure gauge will start to drop as the gas is consumed, but the outlet pressure should be nearly steady as long as at least 2–3 times the outlet pressure remains on the high-pressure side. Restore the cylinder valve to its fully open position. Sometimes it is convenient to run this test while waiting for the gas lines to be purged of any small amount of air that entered during installation.

As with all components in the GC supply gas stream, the connecting tubing and fittings need to be free of contaminants and leaks, and they must be rated to withstand the highest possible pressure to which they could be subjected in the event of pressure regulator failure. A good figure of merit to use is at least twice the opening pressure of the safety relief valve in the downstream pressure side of the regulator, which will be greater than the highest outlet pressure the regulator is designed to deliver. Even so, higher-pressure transients are possible with failure of the high-pressure side of the regulator, until the contents of the cylinder have been vented.

For the above reasons, GC installations should never use polymeric tubing or plastic fittings. Although such materials are suitable for many liquid chromatography (LC) applications, they are not suitable for GC use for three reasons. First, polymeric materials may contaminate the gas stream. Atmospheric gases, namely water and oxygen, may diffuse into the gas stream, and the tubing can emit traces of plasticizers. Second, polymeric tubing and fittings may fail and burst at high pressures. And third, when routed behind a GC instrument, polymeric tubing and fittings may be exposed to the high-temperature air exhaust from a GC oven that is cooling down, which could cause an immediate tubing failure or at least weaken a section of the tubing.

I’ve seen a few installations that use aluminum tubing, but this is not a suitable choice. Although aluminum possibly is less expensive than copper or stainless steel, it lacks the ductility of other available metal tubing, and it will rapidly develop metal fatigue cracks and failures unless it is mechanically constrained. The majority of GC gas supply installations will flex the connecting tubing during tank changes, and with some GC systems the external connecting tubing is flexed when the top cover is lifted. In addition, aluminum tubing does not fare well in swaged fittings that must be disconnected and remade.

When the residual cylinder pressure drops below about three times the regulator outlet pressure, which is around 250 psig (1.7 MPa), it’s time to replace the cylinder. Don’t allow the internal cylinder pressure to go to zero; it will force the gas supplier to perform extra cleaning on the cylinder because they cannot assume it has not been contaminated. In addition, running down the cylinder pressure will cause the regulator’s outlet pressure first to increase slightly and then drop off toward zero, which will cause retention time and detector stability problems. First bring a new cylinder into the laboratory, and then swap the old and new cylinders as follows.

The pressure regulator must be relieved of internal gas pressure before it is disconnected; otherwise a sudden burst of gas may result. First, turn the GC thermal zones off and allow them to cool. Turn off the detectors as well. Then turn off the high-pressure cylinder valve and allow both the high-pressure and outlet pressure gauges to approach zero. It may be necessary to bleed gas off at the GC by increasing a flow or pressure setting temporarily. Next, set the pressure adjustment on the regulator fully off and close the regulator outlet valve. Turn the GC flow and pressure settings to zero to prevent air from diffusing back into the gas lines and filters. Finally, loosen and remove the regulator from the gas cylinder, and install the cylinder cap.

Carefully secure the regulator while exchanging the cylinders. A small strap or chain works well to hold it onto a neighboring device, or just place it on a flat surface. Don’t leave it hanging by the connecting tubing, which will only stress the tubing and could allow the regulator to fall some distance and be damaged.

If a regulator will be removed from use, even for a day, it should be detached from the connecting tubing and stored in a dust-free environment. If gas filters are in-line, be sure they are filled with gas and then if possible, seal the filters’ inlets and outlets before exposing the gas supply lines to the open air.

Return used cylinders promptly. Keeping empty cylinders on hand will accumulate cylinder demurrage charges and waste space that could be put to better use.

Laboratory workers can ensure high-pressure gas cylinder safety by following a few simple procedures and installation guidelines. Proper cylinder restraint, appropriate regulator installation and operation, and suitable connecting tubing and fittings all will yield improved safety and better GC results. Cylinder transportation is the most hazardous part of gas handling in the laboratory environment. Perhaps risky gas handling behavior is due to simple carelessness and a rush to get the instruments up and running again, but the potential cost and impact of not following safe procedures far outweighs the loss of a few minutes of productive lab time.

Are cylinders stored in upright positions and immobilized by chains or other means to prevent them from being knocked over? [CGA 3.4.4 and 29 CFR 1910.101(b)]Note: Tragic accidents have occurred when a cylinder was knocked over, damaging the cylinder and turning it into a rocket.

Are cylinders stored away from electrical connections, gas flames or other sources of ignition, and substances such as flammable solvents and combustible waste material? [CGA 3.5.1]

Are flammable gases separated from oxidizing gases in storage areas? [CGA 3.3.3]Note: Acetylene and propane cylinders should be separated from oxygen cylinders when not in use.

Are oxygen and fuel gas cylinders separated by a minimum of 20 feet when in storage? [CGA 3.5.3]Note: A fire-resistant partition between the cylinders can also be used.

Are storage rooms for cylinders dry, cool, and well- ventilated? [CGA 3.3.5]Note: The storage rooms should be fire resistant and the storage should not be in subsurface locations. Cylinders should be stored in secure areas at temperatures below 125ºF, away from radiators or other sources of heat.

Are cylinders stored away from incompatibles, excessive heat, continuous dampness, salt or other corrosive chemicals, and any areas that may subject them to damage? [CGA 3.3.7 and 29 CFR 1910.101(b)]Note: Rusting will damage the cylinder and may cause the valve protection cap to stick.

Are all compressed gas cylinders subjected to periodic hydrostatic testing and interior inspection? [29 CFR 1910.101(a)]Note: This is normally done by the supplier.

Are cylinders always maintained at temperatures below 125ºF? [CGA 3.1.12]Note: A flame should never come in contact with any part of a compressed gas cylinder.

Is repair or alteration to the cylinder, valve, or safety relief devices prohibited? [CGA 3.1.15]Note: All alterations and repairs to the cylinder and valve must be made by the compressed gas vendor. Modification of safety relief devices beyond the tank or regulator should only be made by a competent person appointed by management.

Is painting cylinders without authorization by the owner prohibited? [CGA 3.1.20]Note: Often color codes are used to help designate cylinders. Arbitrary paint is not recommended.

Are all compressed gas cylinders regularly inspected for corrosion, pitting, cuts, gouges, digs, bulges, neck defects and general distortion? [29 CFR 1910.101(a)]

Are cylinder valves closed at all times, except when the valve is in use? [CGA 3.1.15]Note: Regulator diaphragms have failed, and unwanted gas was delivered to an area or apparatus, causing safety and health problems.

Are compressed gas cylinders always moved, even short distances, by a suitable hand truck? [CGA 3.2.6]Note: They must never be dragged across the floor. Serious accidents have occurred when a cylinder with a regulator in place was improperly moved. The cylinder fell, causing the regulator to shear off, and the cylinder rocketed through several brick walls.

Is using wrenches or other tools for opening and closing valves prohibited? [CGA 3.4.9]Note: Hammering on valve wheels to open them should be strictly prohibited. For valves that are hard to open, contact the supplier for instruction

Are suitable pressure regulating devices in use whenever the gas is emitted to systems with pressure-rated limitations lower than the cylinder pressure? [CGA 3.4.5]

Are all compressed gas cylinder connections such as pressure regulators, manifolds, hoses, gauges, and relief valves checked for integrity and tightness? [29 CFR 1910.101(a)]

Are all compressed gas cylinders regularly subjected to leak detection using an approved leak detecting liquid? [29 CFR 1910.101(a)]Note: Ordinary soap solution may contain oils that are unsafe when used with oxygen cylinders. Leak detection liquids are available from commercial welding supply houses.

Are procedures established for when a compressed gas cylinder leak cannot be remedied by simply tightening the valve? [CGA 3.1.6]The procedures should include the following:

Compressed gases are stored in heavy-walled metal cylinders designed, produced and tested for use with compressed gases. Cylinders are made in a wide variety of sizes and shapes. They range from small lecture bottles, often used for demonstration purposes, to large cylinders over 3 metres long. Cylinders for transportation must meet CSA standard CAN/CSA-B339 "Cylinders, Spheres and Tubes for the Transportation of Dangerous Goods". This standard covers requirements for the manufacturing, inspection, testing, marking, requalification, reheat treatment, repair, and rebuilding of cylinders, spheres, and tubes (containers) for the transportation of dangerous goods. In addition, it includes the requirements for the qualification of new designs and registration requirements. You should also consult CAN/CSA-B340 "Selection and Use of Cylinders, Spheres, Tubes, and Other Containers for the Transportation of Dangerous Goods, Class 2".

Cylinders that meet these criteria are often referred to as "TC approved" cylinders. Cylinders are permanently marked, typically on the shoulder or the top surface of its neck.

Compressed gas cylinders must be connected only to regulators and equipment designed for the gas in the cylinder. Since connecting the wrong equipment can be dangerous, a number of different standard cylinder valve outlets are available for different classes of gas. For example, these standard connections prevent the valve connection for a flammable gas from fitting the connections for an incompatible gas, such as an oxidizing gas.

Most compressed gas cylinders have valve caps or some other method of protecting the valve from damage during handling and transportation. A dust cap may be placed over the valve outlet itself to help keep it clean.

Most cylinders have one or more safety-relief devices. These devices can prevent rupture of the cylinder if internal pressure builds up to levels exceeding design limits. Pressure can become dangerously high if a cylinder is exposed to fire or heat, including high storage temperatures.

There are three types of safety-relief devices. Each relieves excessive gas pressures in a different way:Safety- or Pressure-Relief Valves: These valves are usually a part of the cylinder. They are normally held closed by a spring. The force holding the valve closed is set according to the type of gas in the cylinder. The valve opens if the cylinder pressure exceeds the set safety limit. Gas is released until the cylinder pressure drops back to the safety limit. The valve then closes and retains the remaining gas in the cylinder.

Rupture Discs(also known as frangible or bursting discs): These discs are usually made from metal. They burst or rupture at a certain pressure, releasing the gas in the cylinder. The bursting pressure is designed so that the disc ruptures before the cylinder test pressure is reached. These devices cannot be reclosed, so the entire contents of the cylinder are released.

Fusible Plugs(also called fuse or melt plugs): Temperature, not pressure, activates fusible plugs. These safety devices are used where heat could initiate an explosive chemical reaction. A pressure-relief valve or rupture disc acts too slowly and too late to prevent rupture of the cylinder if an explosive reaction has already begun. The fusible plug releases the gas before the hazardous reaction can begin. Fusible plugs are made of metals that melt at low temperatures. For example, acetylene cylinders have a fusible plug which melts at about 100°C (212°F). This temperature is safely below the temperature at which hazardous polymerization may occur.

Not all compressed gas cylinders have safety devices. Some gases are so toxic that their release through a safety device would be hazardous. Cylinders for these gases are built to withstand higher pressures than normal cylinders. When these "toxic gas" cylinders are involved in a fire, the area must be evacuated.

Substitution can be the best way to avoid or reduce a hazard. But it is not always easy or even possible to find a less hazardous substitute for a particular compressed gas used for a certain job. Speak to the chemical supplier to find out if safer substitutes are available. For example, in some cases, methylacetylene-propadiene (MAPP) gas, propylene, propane or mixtures of liquefied petroleum gas can be substituted for acetylene as fuel gases for cutting, welding and brazing. These gases are more stable and can be stored in normal cylinders. Their flammable limits are much narrower than those of acetylene (e.g., 3.4 to 10.8 percent for MAPP versus 2.5 to 82 percent for acetylene), so they represent a reduced fire hazard.

Sometimes, process changes or modifications can reduce a material"s hazards. For example, many cylinders of the same gas may be used in different areas of a workplace. Installing fixed pipelines connected to a central gas supply in a safe area can often reduce the hazard. It can also reduce the need for many sets of portable equipment supplied through flexible hoses. Similarly, ordering cylinders equipped with flow limiting restrictors can minimize the hazards of a sudden failure of a process gas line.

Assess the specific ways your workplace stores, handles, uses and disposes of its compressed gases. An assessment can reveal if existing ventilation controls and other hazard control methods are adequate. Some workplaces may need a complete system of hoods and ducts to provide acceptable ventilation. Others may require a single, well-placed exhaust fan. Storage facilities for particularly hazardous materials such as chlorine, may require an additional emergency ventilation system, or continuous monitoring with appropriate alarms. Other workplaces using small amounts of inert gases may require no special ventilation system.

Make sure ventilation systems are designed and built so that they do not result in an unintended hazard. Ensure that hoods, ducts, air cleaners and fan are made from materials compatible with the gas used. Systems may require explosion-proof and corrosion-resistant equipment. Separate ventilation systems may be needed for some compressed gases to keep them away from systems exhausting incompatible substances.

Store compressed gas cylinders in compliance with the occupational health and safety regulations and fire and building codes applying to your workplace. These laws may specify the permissible kinds of storage areas and the construction of these storage areas. They may also specify the kinds and amounts of different gases that can be stored in each safe storage area.

Inspect all incoming cylinders before storing to ensure they are undamaged and properly labelled. Do not accept delivery of defective cylinders. Be sure they are not giving off odours, visible fumes or hissing sounds. Check that the cylinder was last tested within the required time (usually 5 or 10 years, but some containers may be as low as 3 years or as long as 12 years).

Also check that the cylinder labels are intact and that they match other identifying markings on the cylinder. Do not rely on cylinder colour to identify the gas. Different suppliers may use different colours for cylinders of the same gas. In addition, colours appear different under artificial lights and some people are colour blind. Gases that cannot be clearly identified should not be used.

Call compressed gases by the name on the supplier label. This reduces confusion, promotes recognition of the hazards involved and precautions to take, and can prevent accidental use of the wrong gas. If oxygen is called "air," someone who wants air to run a tool may use oxygen with possible serious results. Leave the valve cap securely in place until the cylinder is to be used. Inspect the cylinder valve by looking through the ports in the valve cap. Do not accept dirty, rusted or otherwise damaged valves and fixtures.

Always transport cylinders with valve caps or other valve protection in place. Pulling cylinders by their valve caps, rolling them on their sides or dragging or sliding them can cause damage. Rolling cylinders on their bottom edge ("milk churning") may be acceptable for short distances. Never lift cylinders with magnets or chain or wire rope slings. Transport cylinders on specially built hand carts or trolleys or other devices designed for this. All transport devices should have some way of securing cylinders to prevent them from falling.

Store compressed gas cylinders separately, away from processing and handling areas, and from incompatible materials. Separate storage can minimize personal injury and damage in case of fires, spills or leaks. Many compressed gases can undergo dangerous reactions if they come in contact with incompatible materials (gases, liquids or solids), so store them apart from each other. For example, store oxidizing gases at least 6 metres (20 feet) away from fuel gases or other combustible materials, or separate them with an approved fire wall. Check the reactivity information and storage requirements sections of the MSDS for details about which materials are incompatible with a particular compressed gas. The National Fire Code addresses requirements for segregation of different gases in storage.

If compressed gas cylinders are stored outside, use a well-drained, securely fenced area. Keep them on a raised concrete pad or non-combustible rack. Protect cylinders from the weather and do not allow them to stand directly on wet soil as this can cause corrosion.

Indoor storage areas must have walls, floors and fittings made of suitable materials. For example, use non-combustible building materials in storage areas for oxidizing gas and corrosion-resistant materials in storage areas for corrosive gas. Make sure floors are level and protect cylinders from dampness. Avoid overcrowding in storage areas or storing cylinders in out-of-the-way locations.

Always chain or securely restrain cylinders in an upright position to a wall, rack or other solid structure wherever they are stored, handled or used. Securing each cylinder individually is best. Stacking of groups of cylinders together offers some protection, but if this is done improperly, the entire group or individual cylinders could fall.

Follow the gas supplier"s recommendations for storage and use temperatures. To prevent excessive pressure buildup, never expose cylinders to temperatures above 52°C (125°F). Do not subject them to temperatures below -29°C (-20°F), unless they are designed for this. Cylinders that become frozen to a surface can be freed by using warm water (less than 52°C). Never apply direct heat to a cylinder.

When moving cylinders, securely fasten them to a suitable cylinder transporting device. At the site, chain or otherwise secure the cylinder in place. Remove the valve cap only after the cylinder has been safely installed then check the cylinder valve and fixture. Remove any dirt or rust. Grit, dirt, oil or dirty water can cause gas leaks if they get into the cylinder valve or gas connection.

There are four standard types of cylinder valve outlets to prevent interchanges of gas handling equipment between incompatible gases. Use only the proper equipment for discharging a particular gas from its cylinder. Never use homemade adaptors or force connections between the cylinder valve outlet and gas handling equipment.

Whether a compressed gas is a liquefied, non-liquefied or dissolved gas, the gas supplier can give the best advice on the most suitable gas discharge equipment and the safest way to use it for a specific job.

In general, do not lubricate any cylinder valves, fittings, or regulator threads, or apply jointing compounds and tape. Use only lubricants and sealants recommended by the gas supplier.

Cylinders stored in cold areas may have frozen valves. Use only warm water to thaw the valve or bring the cylinder into a warm area and allow it to thaw at room temperature.

Use only recommended keys or handwheels to open valves. Never use longer keys or modify keys to increase their leverage. Avoid using even the correct key if it is badly worn. Do not use pipe wrenches or similar tools on handwheels. Any of these practices could easily damage the valve seat or spindle.

Always open valves on all gas discharge equipment slowly. Rapid opening of valves results in rapid compression of the gas in the high-pressure passages leading to the seats. The rapid compression can lead to temperatures high enough to burn out the regulator and valve seats. Many accidents involving oxidizing gases result from burned out regulator and valve seats, usually caused by opening valves too quickly.

Do not use excessive force when opening cylinder valves--use no more than three quarters of a turn if possible. If a problem develops, the valve can then be closed quickly. Leave keys on cylinders when valves are open so the valve can be closed quickly in an emergency. Some cylinder valves, such as oxygen valves, have double seating. These valves should be fully opened, otherwise they may leak.

Do not use excessive force when opening or closing a cylinder valve. When closing, turn it just enough to stop the gas flow completely. Never force the valve shut.

Close cylinder valves when the cylinder is not actually in use. Do not stop the gas flow from a cylinder by just backing off on the regulator. Regulators can develop seat leaks, allowing pressure to build up in equipment attached to the regulator. Also if the cylinder valve is left open, foreign matter can enter the cylinder if the cylinder pressure drops lower than the pressure in attached equipment. Close the cylinder valve first and then close the regulator.

Manual valves are normally used on cylinders containing liquefied gases. Special liquid flow regulators are also available. If it is necessary to remove liquid as well as gas from a cylinder, discuss this with the gas supplier before ordering. Some liquefied gas cylinders have eductor tubes which allow the liquid to be withdrawn from the cylinder. The supplier can provide suitable cylinders and special instructions.

Do not remove gas rapidly. The pressure in the cylinder could drop below the required level. If this happens, or if rapid gas removal is needed, follow the gas supplier"s advice.

There are two basic types of automatic pressure regulators: single-stage, and double- or two-stage. Generally, two-stage regulators deliver a more constant pressure under more precise conditions than single-stage regulators. Sometimes, manual flow controls are used on non-liquefied gases. Fine flow control can be obtained, but an operator must be present at all times. Manual flow controls do not automatically adjust to pressure buildups in blocked systems.

Use the smallest practical cylinder size for a particular job. Do not keep cylinders longer than the supplier recommends. Compressed gas cylinders are mainly shipping containers. They are built to be as light as possible while remaining safe and durable. Do not drop cylinders or otherwise allow them to strike each other. Rough handling, including using cylinders as hammers or as rollers to move equipment, can seriously damage them.

Apart from the fact that it is illegal, it can be dangerous for non-specialists to refill cylinders or to change their contents. Explosions, cylinder contamination or corrosion can result.

All equipment used with compressed gases must be clean, properly designed and maintained, and made from materials compatible with the gas used. For example, acetylene forms explosive compounds in contact with copper, silver and mercury or their alloys, including bronze or brass containing more than 65 percent copper. Ammonia attacks brass and can react with mercury to form an explosive compound. Do not use mercury pressure gauges in ammonia systems.

In general, avoid pressurizing ordinary glass equipment. Use specially designed glass equipment and protective devices. Where cylinders are connected to a manifold or header, make sure specialists properly design and install the system. Use effective flashback arrestors on acetylene and other flammable gas systems.

Always follow the correct procedures for assembling and disassembling compressed gas equipment. Check that all the connections are clean and do not leak. Check for leaks, using the gas suppliers recommended method, after assembling and before starting to use equipment. Never use old clips or twisted wire for hose connections. If a hose works loose and flails around, serious injury could result. Poor hose connections are a common cause of accidents.

Acetylene under pressure can explode. Never use acetylene outside of the cylinder at pressures over 103 kPa (15 psig) unless you take special precautions. If an acetylene cylinder has been accidentally left on its side, set it upright for at least an hour before use. Otherwise, it will emit a burst of solvent instead of gas when the valve is opened.

Corrosive gases can "freeze" the valve stem, making it hard to open the valve. This results from the gas corroding the valve metal. Minimize "freezing" by rotating the valve stem at least once a day while the cylinder is in use. Also, flush the regulator or manual control valve with dry nitrogen or dry air as soon as possible after use.

Special cleaning procedures (equivalent to oxygen service) are required for all equipment to be used with oxidizing gases. There are several ways to do this. Contact your gas supplier for the best methods for specific systems.

Do not oil or grease any equipment that may contact oxidizing gases. Keep greasy hands, rags and gloves away from any part of the cylinder and fittings. Normal body oils are usually not hazardous, although it is a good practice never to touch any surface that may contact an oxidizing gas. Use lubricants and connection or joint sealants recommended by the gas supplier.

Always comply with applicable occupational health and safety laws when working in a confined space. When using compressed gases, including inert gases, in a confined space, be sure to check that all equipment connections are leak-tight. Remove cylinders or connected equipment that are not in use from confined spaces, even during short breaks. Check the air for oxygen levels (high and low). Also check for any possible toxic, corrosive or flammable gases before entering confined spaces and during prolonged work periods. Never work alone.

The amount of material remaining in a non-liquefied or dissolved gas (acetylene) cylinder is directly proportional to the cylinder pressure gauge reading. As the gas is used, the reading on the cylinder pressure gauge drops. When the cylinder pressure gauge reads zero, the cylinder is not really empty. The cylinder still contains gas at atmospheric pressure. Keep a slight positive pressure in the cylinder. Consider it "empty" when the cylinder pressure gauge reads about 172 kPa (25 psig) or when the cylinder will not deliver at least 172 kPa to the outlet pressure gauge.

The pressure in liquefied gas cylinders remains constant at a given temperature as long as any liquid remains in the cylinder. The only way to know how much material remains in a liquefied gas cylinder is to weigh the cylinder. The empty (tare) weight of the cylinder is stamped on its neck or valve stem. Record the net weight of the cylinder contents on a card attached to it. As with non-liquefied and dissolved gases, never empty the cylinder completely. Keep a small amount of material in the cylinder to maintain a slight positive pressure.

Keeping a positive pressure in an "empty" compressed gas cylinder helps to prevent back flow or suck back. This back flow is the drawing-back into the cylinder of contaminants or moist air from a higher pressure system or the atmosphere.

Keep the valves on all "empty" cylinders closed. This practice maintains a positive pressure in them. "Empty" cylinders with open valves can "breathe". Temperature increases or drops in atmospheric pressure can force gas out of the open valve of an empty cylinder. This release could result in hazardous conditions depending on the gas and how much is forced out. Temperature drops or increases in atmospheric pressure can cause air to be drawn in through the open valve. Air could cause a serious contamination and corrosion problem inside the cylinder. When a compressed gas cylinder is "empty," handle it as though it is full since it does contain gas.

Notify the gas supplier if the cylinder or any part of it is damaged or defective, contaminated, or may have been exposed to a possibly hazardous condition such as a fire or electric arc.

Take care when scrapping unserviceable cylinders. Before scrapping, first destroy the cylinder as a pressure vessel. Contact the gas supplier for advice on disposing of unserviceable cylinders.

*Note: Hanging things over a cylinder makes it harder to operate the valve. In addition, clothing may become saturated with a hazardous gas. Clothing saturated with either an oxidizing gas or flammable gas will catch on fire easily and burn intensely. Hang clothes that are even partly saturated with an oxidizing gas or fuel gas in a well-ventilated area for at least 15 minutes to remove trapped gas.

If other methods, such as engineering controls, are not available or effective in controlling exposure to compressed gases, wear suitable personal protective equipment (PPE). Choosing the right PPE for a particular job is essential. Material Safety Data Sheets (MSDSs) should provide general guidance. Also obtain help from someone who knows how to evaluate the hazards of the job and how to select the proper PPE.

When using gases that are harmful by skin contact, wear protective gloves, aprons or other clothing depending on the risk of skin contact. Choose clothing made of materials that resist penetration or damage by the chemical. The MSDS should recommend appropriate materials. If it does not, contact the gas supplier for specific information.

Always wear eye protection when working with compressed gases. Avoid ordinary safety glasses. Use chemical safety goggles instead. In some cases, you should also wear a face shield (with safety glasses or goggles) to protect your face. The current CSA Standard Z94.3, "Eye and Face Protectors,