STORAGE OF FLAMMABLE PRODUCTS

R.D. 379/2001
Regulations regarding the storage of chemical products and the additional technical instructions for specific products and their categories. This section looks at the main characteristics regarding storage, ie: tanks, drums, portable containers, bottles, etc. It also considers the location of the storage, ie: above ground, below ground, inside, cupboards, etc. and the protective measures against the risks that are present in these storage areas.

ADDITIONAL TECHNICAL INSTRUCTIONS FOR FLAMMABLE LIQUIDS “APQ-001”

Product classification:
They are classified as A, A1, A2, B, B1, B2, C and D, depending on their flammability and the conditions of storage.

Combustion temperature or Flashpoint.
This is the minimum temperature at which a flammable liquid gives off enough vapour to create a flammable mixture with the air surrounding the surface of the liquid or inside a container. In the test to determine the flashpoint, a flame is used as a source of ignition.

The liquid is heated slowly from a theoretical lower temperature and as the temperature increases, a flame is applied to the vapour chamber. The point of ignition is the temperature at which a spark is observed when the flame or source of ignition is applied.
Temperature of spontaneous ignition.

This is the minimum temperature at which a substance in contact with air ignites spontaneously without any source of ignition. At this temperature there is enough energy to start combustion.

Spontaneous ignition can sometimes be called the temperature/point of auto-ignition and could also appear as ignition point. It is important to ensure that there is no confusion with the temperature of ignition or flashpoint, especially if data from tests or tables is not available. In cases where these values are not available, it must be assumed that the auto-ignition temperature is much higher than the flashpoint. In the majority of cases this is between 200 and 700 ºC. This parameter should be used as a reference for operations with a significant rise in temperature but without an ignition source such as heat treatment, heat exchangers with insulating oils, covered electric motors, etc.

The ignition temperature of hydrocarbons in the air decreases as the molecular mass increases. For example:
Methane  ................................537 ºC
n-butane ................................405 ºC
n-decane ................................208 ºC

The ignition tempetature of hydrocarbons in the air, eg: paint thinners, decreases as the container ́s size increases

The ignition temperature of toluene is 580 ºC in a container of 0,05 l.
The ignition temperature of toluene is 480 ºC in a container of 15 l.
The ignition temperature of methanol is 475 ºC in a container of  0,05 l.
The ignition temperature of methanol is 375 ºC in a container of 15 l.
The temperature of autoignition can decrease significantly due to a catalyst, such as particles of iron oxide dust, atmospheres rich in oxygen and under high pressures.

CLASS A Liquefied products, whose absolute vapour pressure at 15 °C is greater than 1 bar. Depending on the tem-
perature at which they are stored,, they can be considered as the following:
a. Subclass A1. Products of class A that are stored liquefied at a temperature below  0 °C.
b. Subclass A2. Products of class A that are stored liquefied in other conditions.

CLASS B* Products of which the ignition point is below 55 °C and are not included in class A. Depending on their 
ignition point, can be considered as the following:
a. Subclass B1. Products of class B of which ignition point is below 38 °C.
b. Subclass B2. Products of class B in which the ignition point is equal or greater than 38 °C and below 55 °C.
CLASS C Products which have an ignition point in the range of 55 °C and 100 °C.
CLASS D Products which have an ignition point greater than 100 °C.

ADDITIONAL GUIDANCE FOR STORING FLAMMABLE LIQUIDS“APQ-001” (CONT.)

These technical intructions apply to the storage, loading, unloading and the decanting of flammable liquids, such as paints and thinners, with the following exceptions:

1. Storage with a capacity below 50 l. of class B products, 250 l. of class C or 1,000 l. of  class D.
2. Storage within a process area where the capacity is limited to what is necessary for the continuity of the process.
3. Storage of products where the flamepoint is higher than  150 °C.
4. Storage of products where specific industrial safety regulations exist.

Exclusions that apply to the additional guidance for storing flammable liquids:

1.Internal use in process installations
2.The storage of paint, clearcoat or similar mixtures where they are going to be used within a 30 day period and only once.
3.The temporary storage of products waiting to be redistributed  and where the expected storage will not exceed 72 hours continuously.
In all cases, if the products are to be stored for more than 8 days per month or 36 days per year, the storage cannot be considered temporary and the long term storage guidelines should be followed.

REGISTRATION WITH THE DEPARTMENT OF INDUSTRY

New projects for storing flammable liquids in buildings or non industrial establishments can be part of a larger project or a project on their own. Where a storage facility is being designed on its own, the plans will be drawn up and signed by a competent design engineer. Where the design engineer is not the general project designer, they must work alongside the general architect and comply with the basic aspects of the installation as stated in the general design project of the building.
A project which refers to the storage regulations of chemical products should be composed of the following documents.

TECHNICAL APPENDIX

This should list, as a minimum, the following sections:
Warehousing and containers types, a description of capacities, dimensions and other characteristics. It should list the products to be stored with their safety data sheets and make reference to the regulations regarding new substances and their classification. It should also contain details of the packaging and labelling of harmful substances and the maximum pressures and temperatures expected. It should also demonstrate compliance with the design regulations.
Systems, equipment and methods of protection against fire, defining the regulations, the measures that will be used and carrying out the calculations required.
Other considerations of safety and a description of their characteristics.
The methods used to protect materials against corrosion and/or other dangerous effects.
Information about the transfer of chemicals, their characteristics and quantities.

Study of the classified zones.

Geographical and topological aspects of the surrounding area,considering  natural disasters that may happen, such as, landslides, flooding, etc. and a description of the protective measures required in each case.
Certification of the compliance with these complementary technical instructions or other measures employed.

REGISTRATION WITH THE DEPARMENT OF INDUSTRY (CONT.)

PLANS
These should include the following as a minimum:
Geographical maps preferably using scales 1:25,000 or 1:50,000. Each map should show the storage and access routes, urban concentrations and relevant topographical risks within  a 10km radius centered on the warehouse.
A general map of the area showing the safe distances according to the regulations.
Separate plans of the installation should be provided which should show the position of all fixed fire fighting equipment. A detailed plan of the fire  alarm system should be provided as well as the drainage, antipollution systems and all other safety equipment.
Detailed plans for each type of container and their safety systems should be provided.

PROPOSAL
Instructions for the use, maintenance and the safety of the installation, regarding personnel, goods and the environment.

FOR WAREHOUSES WITH A CAPACITY LESS THAN THE FOLLOWING



The project should be submitted with a written document signed by the owner of the warehouse or it ́s legal representative. This document should describe the products that are going to be stored along with their characteristics. It should also describe the warehouse and all the safety measures that are going to be used.

REGISTRATION WITH THE DEPARMENT OF INDUSTRY (CONT.)

COMMERCIAL PREMISES OPEN TO THE PUBLIC

The quantity of stored liquid must not exceed 0,8 m3 (800 liters) per square meter of floor area, without exceeding the following total quantities of:
0,2 m3 (200 liters) of class A product; 0,25 m3 (250 liters) of product  subclass B1 with boiling point below 38 ºC; 0,5 m3 (500 liters) of product subclass B1 with boiling point of 38 ºC or higher, 1,0 m3 (1,000 liters) of product subclass B2; 2,5 m3 (2,500 liters) of product class C; 10 m3 (10,000 liters) of product class D.

The floor area of the warehouse may be calculated by adding the maximum capacity likely to be reached to the same floor area for adjacent aisles.

For liquids soluble in water within classes B, C and D the above quantities may be doubled. The same applies when the area of storage has an automatic fire extinguising system installed.

Containers shall never exceed one meter in height or be piled one on top of another (whatever is the greater), unless adequate shelves or supports are available. Filling, transferring or handling of liquids in classes A and B1 is not allowed below ground level.

Where these operations are carried out above ground level, a maximum of 0,04 m3 (40 liters) per square meter of floor area must be followed and a low voltage electrical installation must be in operation. This must be installed in accordance with the current regulations for electrical installations in areas with a risk of explosion or fire (EX).
In these buildings, people other than employees from the warehouse are expected to have access.

For example, customers who purchase large quantities of paints and solvents for retail sale, may collect their own stock. A safe and organised warehouse is essential. 

SUMMARY OF REQUIREMENTS FOR COMPLIANCE TO APQ-001

LOCATION OF THE WAREHOUSE

In general, for all warehouses with portable containers having an individual capacity of less than 3,000 liters, the unstable liquids of classes B, C and D should be treated as if they were a product of subclass B1. Flammable aerosols should be treated as if they were of subclass B2.
Storage of product classes A and B1 are not allowed underground.

PROTECTION AGAINST RISKS

A. Transport: Portable containers must comply with the dangerous goods blity road regulations (ADR).

B. Pressure relief valves: Containers which have a capacity greater than 250l. should have an emergency venting valve. The capacity of this valve must not be less than the capacity on a fixed container. Thermal relief devices, such as fusible plugs, should be used when the product may block other methods of venting. The operating temperature of these devices must not be greater than 150 ºC.

C. Volumes and quantities: When liquids of mixed classes are to be stored in the same stack or shelf, the whole group of liquids should be treated as being in the most restrictive class. If the warehouse is organised in stacks or separate shelves, the total quantities stored must not exceed the quantities permitted for each class.

D. Evacuation: Warehouses within buildings must have at least two independent escape routes, which are clearly signed. The length of the emergency exit corridor must not be greater than 25 m. Access to other areas should have 60 min. automatic fire doors. The corridor should be a minimum of 1 m. wide, except where specific warehouses demand a greater width.

E. Electrical installation: It should comply with the current regulations for areas with a risk of explosion (EX). It should also comply with regulation MI-BT-026.

F. Location: Where shelving is used with wooden shelves or platforms, they must be strong and have a minimum thickness of 25 mm. The containers should be packed, palletised and stacked ensuring stability and following the maximum stacking height. This is to prevent excessive weight in the lower pallets. The highest point of the stored products must be at least 1 meter below any beam,  building structure, sprinkler head or other vertical obstruction. This height must not exceed the values given in tables II and III of section three of the ITC.

G. Ventilation: The warehouse must have natural or forced ventilation. This must comply with regulation 3 of section three of the ITC.

H. Spillages: The floor and the first 100 mm of the walls around the warehouse area should be resistant to liquids including doors and openings.
Alternatively, the floor may drain to a safe place.

I. Protection against fire: Section three of the ITC lists the necessary fire protection measures for mobile containers and are shown in section 5, of table 5.

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