Safety Advice. 9 – Handling and usage of dry ice. - Linde Gas Benelux

Safety Advice.9 – Handling and usage of dry ice.Safe use of dry ice safely means beingaware of its properties and the associatedhazards.1. PropertiesDry ice is Carbon dioxide (CO 2 ) in a solidstate. Its temperature is –78,6C° (194,51K).At room temperature it will transfer directlyinto gaseous form without residues. Thisprocedure is known as sublimation. It isconnected to an important increase involume: 1 kg of dry ice will lead to approximately541 l of CO 2 gas.CO 2 gas is not flammable and is withoutodour or taste. It is not toxic, approved asfood additive.Since CO 2 is 1,5 times heavier than air, itusually sinks down to the floor level of anyroom. This property leads to some importantrules that consequently need to betaken into account when using dry ice.Low temperature warning2. HazardsCO 2 is a typical metabolic substancepresent in body fluids and tissues. It is acomponent of most of metabolic reactionsand acts as a control substance for variousmechanisms of the circulation system, suchas breathing, metabolism, ph-control inblood etc.Danger of asphyxiationThe impact of breathing low volumes ofCO 2 is physiologically negligible. But highconcentrations of CO 2 may provoke asphyxiation.The effect of CO 2 is totally independent ofthe impact of low oxygen concentrations.The oxygen concentration in air is by nomeans an efficient measurement of thepotential hazard of high CO 2 concentrations:it is possible to have an acceptable(low) concentration of oxygen of forexample, 18% but at the same time havinga dangerous CO 2 concentration of higherthan 5%.It is highly recommended therefore topermanently measure CO 2 concentrationsin risk areas e.g. by using a personal gasdetector.The Occupational Exposure Limit value is5.000 ppm (0,5 vol-%) which is calculatedas an average concentration in air during aperiod of 8 hours. The maximum allowableworkplace concentration is 10.000 ppm(1 vol-%) for not more than twice an houror 4 times a day.Due to the high molecular weight of CO 2it rapidly accumulates in lower levels ofclosed environments and will stay thereunless the environment is equipped witheffective ventilation or an extractionsystem.Rescue of injured people in CO 2 enrichedatmosphere is only allowed when usingsupplied air respiratory protective devices.Dry ice has a temperature of –78,6°C andleads to frostbites if in direct contact withthe skin. During the handling of dry ice it ismandatory to use insulated gloves and eyeprotection, in particular during blasting andcleaning activities.Safety Advice. 9 – Handling and usage of dry ice. Page 1

The following rules must be followed:Never handle dry ice without insulatedgloves. This will immediately lead tofrostbite.Always handle dry ice with insulatedgloves or other appropriate tools. When itcomes to special uses such as blasting orcleaning with dry ice, eye and face protectionis highly recommended.Make sure that children and other notauthorized people are not in contact withdry ice.Store dry ice safely away from children.Dry ice is not ice cream! Swallowing dryice is extremely dangerous!Never store or use dry ice in cellars orsmall rooms without sufficient ventilation.CO 2 is significantly heavier than air and willaccumulate constantly in lower levels ofthe room.Handle and use dry ice only with sufficientventilation including the floor. In case ofdoubt, use mechanical ventilation andgas detectors. Small areas like vesselsand containers may only be entered withappropriate protective measures.Never store dry ice in air tight vessels.Warm temperature causes formation ofhigh amounts of gas. This may lead to thebursting of the vessel!Only use appropriate storage vessels. Dryice containers must be able to „breathe“.Dry ice should not be transported in thecabin of a car. If dry ice is left for longerthan 30 minutes in a closed room (e.g. car,luggage – or loading space, container etc),the doors or windows should be openedfor at least one minute prior to unloadingin order to assure sufficient ventilation.Dry ice should always be transported ina separate compartment from the driver.Never leave dry ice in the car for a longperiod of time.Advice regarding vaporisation (sublimation):Depending on the temperature and the insulation of the transport vessel, 2 – 20% of the material may sublimate per day. The resultingcold gas provokes the formation of water ice along the seals of the vessel. This is a normal procedure.Further information regarding Carbon dioxide is available at the Safety Advice No. 12 – “Handling of Carbon dioxide”.Dry ice hotline: 01803.85000-0Linde AGLinde Gas Division, Linde Gas Germany, Seitnerstraße 70, 82049 PullachPhone 018 03.85 000-0*, Fax 018 03.85 000- 1, www.linde-gas.comSafety Advice. 9 – Handling and usage of dry ice. Page 2