fabric. Tears in the material offer avenues through which spilled oil 

 can escape, thereby reducing the overall effectiveness of the boom. 



The resistance to tear propagation applies primarily to the fence 

 material rather than to the flotation material unless the flotation 

 actually serves as a portion of the vertical barrier. The resistance to 

 the propagation can be measured by testing the material in accordance 

 with FTMS 191 Method 5134. For acceptibility, a material must exhibit a 

 tear strength in both the warp and fill directions of 200 pounds as 

 specified in MIL-B-2861 7B (YD). 



Adhesion of Coating. The coating on the material must not separate 

 from the fabric when the material is under stress. Such separation 

 weakens the material, exposes the fibers to the environment, and short- 

 ens the life of the boom. MIL-B-2861 7B (YD) invokes FTMS 191 Method 

 5970 for determining the adhesion of the coating. However, an acceptable 

 capacity for adhesion is not specified. Instead, the specification 

 requires an 80% retention in adhesive capacity after immersion in fresh 

 water for 16 days at 120 F. Stating the requirement in this manner 

 avoids conflict with the requirement for tear resistance. Generally, 

 the adhesion of the coating varies inversely with the tear resistance 

 of the material. The greater the adhesive strength, the less tendency 

 there is for the fabric fibers to rope up as the material is torn. The 

 coated material will therefore tear much more easily then the uncoated 

 fabric. 



Puncture Resistance. Punctures can occur in booms during all 

 phases of operation and handling. The ability of a fabric to resist 

 punctures from sharp objects is especially important for booms using 

 inflatable flotation members or those using beads or chips of flotation 

 material enclosed in a chamber. If these members are punctured, the 

 flotation medium can escape and that portion of the boom may sink, thus 

 permitting spilled oil to pass over. Punctures also weaken the material 

 and breaking or tearing under operational tensile loads can occur. 



A standard test method for measuring the puncture resistance of 

 flexible barrier materials is FTMS 10TB Method 2065. This method 

 specifies that an increasing load be applied to the material using a 

 moving probe to determine the force required to puncture. Another 

 method that has been used to measure the puncture resistance of tarpaulin 

 fabrics employs a puncture comparator machine [4]. With this device a 

 needle-pointed projectile is dropped a specified distance down a shaft 

 where it pierces a tightly held section of the test material. The 

 distance the projectile penetrates the material is an indication of the 

 relative puncture resistance. 



Abrasion Resistance. The material must be capable of withstanding 

 mechanical action that tends to remove material from its surface, such 

 as rubbing, scraping, or erosion. Abrasion damage to the boom weakens 

 the material and is incurred in much the same manner as tears and punc- 

 tures. Not only is the structural strength lowered but resistance to 

 chemicals and water absorption are lowered, thereby shortening a boom's 

 useful life and increasing maintenance requirements. 



