caustic soda handling procedure

Safe handling of caustic soda

HMESC: 01.40.03.201 Date: July 2010 Issue: 01 Page: 1 of 7

Rules, Standards & Procedures

Safety Procedure

SAFE HANDLING OF CAUSTIC SODA (SODIUM HYDROXIDE)

Contents

1. OBJECTIVE 2

2. SCOPE 2

3. DEFINITIONS 3

4. REQUIREMENTS 3

5. VERIFICATION 7

6. IMPLEMENTATION SCHEDULE 7

7. REFERENCES 7




Safety Procedure

1. OBJECTIVE

The objective of this standard is to set requirements for the safe handling of caustic soda (= sodium hydroxide) in order to assure an appropriate level of protection of personnel. Mandatory is:

To train all personnel potentially exposed to caustic soda regularly how to handle caustic soda safely, how to use PPE and how to deal with caustic soda exposure (documented);

To provide personnel with possible caustic soda exposure with the appropriate PPE, at least chemical splash resistant safety goggles and chemical resistant gloves;

To apply media coding, safety signs, first aid instructions at places of possible caustic exposure;

To have safety showers and eyewash fountains operational (regularly inspected and tested) at places with risk of severe caustic exposure;

2. SCOPE

The standard applies to all storage, handling, use and discharge of caustic soda (= sodium hydroxide or NaOH) or abbreviated to caustic. Caustic soda is used:

- in water treatment as neutralisation agent, regenerant of cation exchangers as 2%-5% solution; - in process installations as cleaning agent as 1% - 3% solution; - in process installations as deep cleaning as 2 – 5% solution - in the regeneration of PVPP as 2% solution; - in kegs and bottle cleaning as 2% - 3% solution; - in wastewater treatment for pH control as 5 % - 10% solution;

So caustic soda can be found in many places in the Production Unit (brewery, soft drink plant or cider mill). The caustic soda is supplied and stored in concentrated form:

- as solid in bags (flakes, pellets, granules) as 98% NaOH - as liquid of 30% - 50% NaOH

.The caustic soda is generally diluted to the user concentration at the Production Unit. The exposure of caustic soda to personnel can take place:

- reception of caustic soda from supplier (truck unloading) - preparation of caustic soda solutions at desired concentration (especially manual dilution) - intervention in process installations containing caustic soda (trouble-shooting, maintenance, sampling) - unintended exposure due to failing equipment (caustic soda sprays due to leakage) or wrong preparation - contact with waste caustic soda e.g. in sewer system (overflow)




Safety Procedure

3. DEFINITIONS

Sodium hydroxide Chemical substance with chemical formula NaOH. A white non-combustible solid. In contact with water, it will generate substantial heat. The solid and its solutions are corrosive. NaOH is odourless, so does not provide a warning of hazardous concentrations. It can cause severe burns in all tissues, in particular eyes. EC nr 215-185-5 CAS nr 1310-73-2 Sodium hydroxide has not been classified for carcinogenic effects.

Solid sodium hydroxide Can be in the form of flakes or pellets with 98% NaOH

Sodium hydroxide solution Trade solution between 30 - 50wt% NaOH User solutions between 1 - 10% NaOH

IBC Intermediate Bulk Container

PVPP Polyvinylpolypyrrolidone used for beer stabilisation

PPE Personal Protective Equipment

4. REQUIREMENTS

4.1. GENERAL

The Manager of the Operating Unit is responsible:

To comply with the prevailing legislation on the storage, handling, use and discharge of caustic soda;

To train personnel on the dangers of caustic soda, preventive measures;

To make all necessary PPE and clothing available to personnel working with caustic;

To have procedures in place when working with caustic soda;

To investigate caustic soda incidents and accidents to review and improve procedures;

To display first aid instructions at high risk areas;

To mark all caustic soda lines with medium coding : fluid and concentration;

To have safety showers / eyewash fountains operational (inspections !) in places where contact with caustic soda can arise;

4.2 CHARACTERISTICS OF CAUSTIC SODA EXPOSURE

The extent of toxicity due to caustic exposure is determined by several factors:

duration of contact,

ability to penetrate human tissues,

caustic concentration,

caustic temperature and

volume of exposure; Human tissue exposed to an alkaline compound results in tissue penetration of hydroxide (OH-) ions, causing liquefactive necrosis. Liquefactive necrosis is the dissolution of proteins, the destruction of collagen, fat saponification, cell membrane emulsification, transmural thrombosis and cell death. Tissue necrosis following exposure to caustic can occur in minutes. The longer the contact time, the greater the risk of increased area of necrosis.




Safety Procedure

Caustic soda is classified according to EU Regulation 1272/2008 (page 353):

Concentration Risk Explanation

> 5% C, R35

C = corrosive R35 = causes severe burns

2 – 5% C R34

C= corrosive R34 = causes burns

0.5 – 2% Xi R36/R38

Xi = irritant R36 = irritating to eyes R38 = irritating to skin Human skin irritation test (EU Risk Assessment Report): 0.5% caustic : half of volunteers showed a skin irritation reaction within 1 hour 1% caustic : half of volunteers showed a skin irritation reaction within 30 minutes > 1.2 % caustic : likely corrosive properties to eyes (animal study)

< 0.5% No skin irritation or corrosion has been observed (EU Risk Assessment Report)

The safety measures according to EU Regulation 1272/2008 (page 353) to be taken are: S (1/2) – 26 37/39 – 45

S1 = keep locked up

S2 = keep out of the reach of children

S 26 =In case of contact with eyes, rinse immediately with plenty of water and seek medical advice

S37 = Wear suitable gloves

S38 = In case of insufficient ventilation, wear suitable respiratory equipment

S39 = wear eye/ face protection

S45 = In case of accident or you feel unwell, seek medical advice immediately (show the label where possible)

Inhalation of NaOH dust, mist or aerosol may cause irritation of the mucous membranes of the nose, throat and respiratory tract. Mucous membrane irritation occurs at OSHA PEL (Permissible Exposure Limit) of 2 mg/m3. Swelling or spasms of the larynx leading to upper-airway obstruction and asphyxia can occur after high-dose inhalation. Skin contact with solid sodium hydroxide or its concentrated solutions (> 5%) can cause severe burns with deep ulcerations. Burns appear soft and moist and are very painful. Contact with concentrated solutions with any part of the body causes immediate pain and irritation within 3 minutes. Contact with dilute solutions (< 2%) may not cause symptoms for several hours, but serious burns can result when not washed off quickly. Spilling sodium hydroxide over large areas of the skin may cause shock and even death. A serious eye exposure can result in blindness.




Safety Procedure

4.3 RISK OF CAUSTIC SODA EXPOSURE AND PREVENTIVE MEASURES

The risk of caustic exposure and resulting injuries can be calculated by: Risk = E (Effect or possible injury)* D (Duration or frequency of exposure) * P (Probability), e.g. using the Fine-Kinney method. E = Effect of possible injury, depends on

Concentration of the caustic solution

The surface area of skin affected (volume of caustic spilled)

Temperature of the caustic (hot or cold) D = Duration or frequency of the exposure

The contact time between caustic and skin

(Lack of safety provisions like safety shower or eye wash) P = Probability

Availability of Standard Operating Procedures

Training of personnel working with caustic

Presence of correct PPE, discipline to wear PPE

Presence of safety shower and eyewash

Presence of media coding on piping, safety signs

Pressurised caustic solution In the table below the preventive measures are given based on the risk per task.

Task Risk Preventive measures

Unloading of concentrated caustic in bulk

Spray, leakage through connection, defective hose

S G I

Caustic storage tank with containment, hoses and valves in good condition, Unloading procedure, training Full face mask, safety suit,

IBC, jerry can handling Splash, contact through defective closure, punctured container

S G I

Labelling of chemicals as corrosive, containers in good condition Procedure for leaking containers Safety goggles, safety gloves

Handling bags with caustic pellets, flakes

Dust exposure by defective bag

S G I

Handling with minimum contact with bags Safety goggles and safety mask

Preparation of diluted caustic solutions, e.g. for deep cleaning of brewhouse equipment, pasteuriser

Mists, spattering, violent eruption and overboiling

S G I

Equipment designed to dissolve or dilute caustic (mixing, slow addition) Procedure for dissolving caustic Safety goggles/full face mask, safety gloves

Cleaning of process installations/ lines (CIP)

Leakage of valves, joints S G I

Regular inspection Procedure in case of leakage (check with litmus paper) Safety goggles, safety gloves

Supervising water/ wastewater treatment, PVPP regeneration, bottle washer

Leakage of valves, lines S G I

Regular inspection Procedure in case of leakage (check with litmus paper) Safety goggles, safety gloves

S = Preventive measures at the source G = General preventive measures I = Individual preventive measures

DILUTION OF CAUSTIC SODA

Always add caustic soda to the water and never add water to the caustic soda. Mixing of caustic soda and water will cause the liquid to rise in temperature. Careful addition of the caustic to the water ensures dissipation of the heat of dissolution into the liquid. Always use lukewarm water (25 – 38 C), never start with cold or hot water.

If water is added to the caustic, or the caustic soda is added too quickly, a rapid temperature increase can

occur causing the formation of dangerous mists, spattering, boiling or an immediate violent eruption. These conditions can result is severe bodily injury.




Safety Procedure

CAUSTIC SPILLS

Do not discharge caustic spills into sewer systems, onto the ground or open waters. Try to contain the spill, slowly neutralise the contaminated area with diluted acid, preferably acetic acid. Drain and properly dispose off the neutralised solution, in accordance with local environmental regulations.

4.4 PERSONAL PROTECTIVE EQUIPMENT

The minimum to wear are:

safety goggles close fitting, protecting eyes from all sides and

chemical protective gloves. Chemical splash goggles according to ANSI Z87.1 or EN 166-1B:

Chemical resistant gloves (neoprene, nitrile or latex) according to ANSI 105 or EN374:

Effective use of proper PPE to protect the skin may reduce the external exposure with 90%. In contrary, improper PPE can result in increased absorption through the skin. Additional protective equipment is required when dealing with concentrated caustic solutions, risk of substantial exposure, emergency situations:

transparent face shield

chemical protective safety boots

chemical protective full body suit : coat over pants and pant legs over the boots

preferably an additional person in the direct vicinity is recommended Assure that large volumes of water are available for first aid, through safety showers and eyewash fountains (continuous flow and low pressure). The safety showers and eyewash fountains must be easily accessible and operational. The safety shower and eyewash should be reachable within approx. 10 seconds. After contact with caustic soda, never touch your eyes or skin with the gloves that have been contaminated with caustic soda. Wash out your PPE after usage. Never breath dust, mist which may cause irritation to the upper respiratory tract. Never enter tanks or containers which could contain caustic soda e.g. after cleaning. If entry is necessary, drain the tank and flush it thoroughly with water prior to entry, To be sure, test the pH before entering




Safety Procedure

FIRST AID:

In all cases the caustic soda must be removed as quickly as possible by washing with water only. Serious permanent injury can occur in seconds. If wearing goggles, do not remove till washing out has been completed (splashes can contaminate the eyes). Water is the only accepted method for the removal of caustic soda. Do not use soap and do not neutralize caustic soda with chemicals. Seek medical help immediately while continuing washing if possible. Eye contact:

Wash eyes immediately and continuously with plenty of water for at least 30 minutes, while holding eyelids open and rolling eyes back and forth

Call immediately a doctor and continue flushing until the doctor advises to stop Skin contact

Do not remove the chemical goggles

Immediately shower with large volumes of water for at least 30 minutes

Remove contaminated clothing and shoes while showering

Remove chemical goggles last to keep caustic from washing into the eyes

Call immediately a doctor and continue flushing until the doctor advises to stop

Do not apply oils, lotions or acids to the burned area

If the person goes into shock, make sure the person is laying down and kept warm until the doctor arrives

If you help a person, use PPE to protect yourself

Do not pull shirt over the head (cut it off) as this could transfer caustic in the eyes or airways.

5. VERIFICATION

The following documents have to be present (e.g. in case of an internal or external audit):

Standard Operating Procedures for acceptance, storage, handling, use and discharge of caustic;

Training material and records for safe handling of caustic;

Safety shower, eye wash and Safety Data Sheet where a reasonable risk of caustic exposure exists;

Media coding and safety signs at appropriate places

6. IMPLEMENTATION SCHEDULE

The measures shall be implemented as soon as possible.

7. REFERENCES

EU Regulation 1272/2008 on classification, labelling and packaging of substances and mixtures, amending and repealing Directive 67/548/EEC and 1999/45/EC and amending Regulation 1907/2006

Council Directive 2006/102/EC on classification, labelling, packaging of dangerous substances

See MSDS and safety instructions of your caustic supplier or e.g. Liquid Caustic Soda : safe handling and first aid (DOW Chemical Company)

European Union Risk Assessment Report : Sodium Hydroxide

caustic soda handling procedure

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