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					BE SAFE

     O F S O L I D P O LY E S T E R R E S I N S &


                                                   Filago, Italy
      This brochure is only available in English
Solid polyesters are polymers made from organic acids
and glycols. They are processed into flakes, lumps or
powder. The main hazards are determined by the
explosion properties of the dust.


Explosion properties                                           Typical values of explosion characteristics of solid
Dust explosions occur when a cloud of dust (containing         polyester resins & binders dust particles (according to
small particles) mixed with sufficient oxygen (e.g. air) is    VDI 2263; NFPA 68) (indicative)
Dust explosions are not possible if:                            Characteristic                               Typical value
o the dust particles are bigger than 500 µm;
o oxygen (air) is absent or is present in low                   Vol. Res ( in Ω.m)                           1011-1015
o no sources of ignition are present;                           MIE of small particles (< 63 µm) (in mJ)     < 20
o the dust particles are difficult to ignite.
                                                                Pmax (in bar)                                7-10
Important characteristics indicating sensitivity to dust
explosions are:                                                 Kmax (in bar.m.s-1)                          80-180
o the possibility of electrostatic charging (expressed in       Dust explosion class                         St 1
 Volume Resistivity Vol. Res in Ω.m);
o The minimum energy required to ignite the dust-air           Types of solid polyester
 mixture (MIE in mJ). The severity of a dust explosion is      The different types of solid polyester are:
 expressed as:
o the maximum pressure (Pmax in bar);                          - Unsaturated polyester resin for moulding compounds
o the maximum pressure rise time per m3                          (powder or lumps);
 (Kmax in bar.m.s-1).                                          - Resins for binders (powder).

Due to the brittleness of solid polyester all forms (flakes,   These products are not known to emit organic gases.
powder or lumps) can form a fraction of very fine particles
in certain parts of the plant.                                 Particle size distribution of solid binder resin which is
                                                               supplied as powder (indicative)
As regards sensitivity to dust explosions (see table) it can
be concluded that small particles ( < 63 µm) from solid         Product type                                 Typical value
polyester                                                                                                    D50 (in µm)
o can be ignited by low-energy discharge sparks;
o can become electrostatically charged and are therefore        Binder resin                                 125
 sensitive to dust explosions.
In case of emergency call
the following telephone number:       + 31 46 476 5555
What can be done to protect against dust explosions             Explosion suppression
There are several ways to protect against a dust explo-         There are explosion suppression systems on the market
sion, depending on the particle size distribution of the        that detect the start of an occurring dust explosion and
powder and the way the polyester is processed in the            very quickly blow an appropriate amount of inert gas into
plant.                                                          the equipment. This will extinguish the dust explosion
                                                                before the design pressure of the equipment is reached.
General advice cannot be given. If you are not sure of the      The explosion will be contained in the equipment.
safety of the plant or if a new plant is to be designed, you    Suppression systems should be installed in collaboration
need to consult an expert.                                      with the suppliers.

General preventive measures                                     Explosion venting
Avoid the formation of dust clouds in your equipment, e.g.      If a dust explosion starts in the process equipment, the
via good plant design and good housekeeping. The dust           gas pressure generated is released through a bursting
particles are sensitive to static charging, so use highly       disk or an explosion panel. This reduces the final pressure
conductive materials and a well-earthed plant.                  to an acceptable level (lower than the design pressure of
                                                                the equipment). The required vent area depends on the
Explosion-proof design                                          dust explosion characteristics, vessel volume, design
The design pressure of the equipment must be high               pressure of the vessel, etc. The location of the vent panels
enough to withstand the maximum explosion pressure              must be such that any pressure waves or flames are
(Pmax). In cases where explosions are expected to occur         diverted to a safe location and do not harm people or
regularly, an explosion-proof design might be considered.       equipment. For a proper design, dust explosion characte-
                                                                ristics such as Kmax must be known.
Explosion-shock-resistant design
This protection is comparable to explosion-proof design.        Compartmentation
However, unlike the above method, the equipment is              After a (primary) dust explosion a pressure wave, followed
designed such that deformation without rupture is allo-         by flames, could spread to other locations. The pressure
wed.                                                            wave whirls up dust layers, generating dust-air mixtures,
                                                                which ignite as a result of the flames of the primary explo-
Inertization                                                    sion. These secondary explosions are often more violent
If the air in the equipment is replaced by inert gasses (e.g.   than the primary one because of the high degree of turbu-
N2 or CO2), an explosion is impossible. (Partial) inertiza-     lence at the moment of the ignition. To prevent secondary
tion is a suitable prevention method to safeguard process       explosions in buildings, good house keeping is strongly
equipment. If this method is chosen, we recommend that          recommended. Further, compartmentation of the process
the Limiting Oxygen Concentration (LOC) of the dust/air         parts is required to prevent secondary explosions in other
mixtures be measured and that the oxygen content during         parts of the process. This can be achieved by devices
processing be monitored. Inertization is adequate if the        such as quick-closing valves, rotary-valve suppression
O2 is 2-3 vol% below the LOC. (Note: the LOC is different       systems, back-flash interrupters etc. These devices
if CO2 or N2 is used.)                                          should be installed in collaboration with the suppliers.

Polyester Resins Sales Offices

DSM France S.A.                                DSM United Kingdom Limited
Tour Atlantique                                DSM House
9, Place de la Pyramide                        Papermill Drive
La Défense 9                                   Redditch, Worchestershire B 98 8QJ
92911 Paris La Défense Cedex                   UNITED KINGDOM
                                               Tel. (+44) 1 527 590590
Tel. (+33) 1 4125 0505                         Fax (+44) 1 527 590555
Fax (+33) 1 4776 0100

DSM BASF Structural Resins Deutschland GmbH
Building U 508                                 Sizings & Binders Sales Offices
Carl-Bosch-Strasse 38
67056 Ludwigshafen                             DSM China Shanghai Rep. Office
GERMANY                                        Shanghai Square, Suite 1503
                                               138 Huaihai Zhong Lu
Tel. (+49) 621 60 42503                        Shanghai 200021
Fax (+49) 621 60 20733                         P.R. China

DSM Italia Sales Office srl                    Tel. + (86) 21 6375 6148
Via Silvio Pellico 12                          Fax + (86) 21 6375 6146/7
P.O. Box 321
22100 Como                                     DSM Italia Sales Office srl
ITALY                                          Via Silvio Pellico 12
                                               P.O. Box 321
Tel. (+39) 031 236111                          22100 Como
Fax (+39) 031 236790                           ITALY

For Benelux and Export                         Tel. (+39) 031 236111
DSM Sales International bv                     Fax: (+39) 031 510000
Poststraat 1
P.O. Box 43                                    DSM Industrial Resins Inc.
6130 AA Sittard                                Augusta Riverfront Center, Suite 580
THE NETHERLANDS                                One 10th Street
                                               Augusta, Georgia 30901
Tel. (+31) 46 47 73425                         USA
Fax Benelux (+31) 46 47 73409
Fax Export (+31) 46 47 73412                   Tel. (+1) 706 849 6700
                                               Fax (+1) 706 849 6777
DSM España SA
Edificio EURO-3
c./Frederic Mompou 5
Planta 7, Pta. 3-4
08960 Sant Just Desvern (Barcelona)
SPAIN                                         Although the information contained in this document is belie-
                                              ved to be correct as of the date hereof, DSM makes no repre-
Tel. (+34) 93 470 3030                        sentation as to the completeness or accuracy in this docu-
Fax (+34) 93 473 6373                         ment. Those who use this product described herein must
                                              determine the appropriate manner for processing the product
DSM Resins Scandinavia AB                     to insure the safety and quality. In no event shall DSM be
Varvsvägen                                    responsible for damages of any nature resulting from the use of
P.O. Box 619                                  or reliance upon the information contained herein.
26126 Landskrona

Tel. (+46) 418 56670
Fax (+46) 418 22466