A Call For International Regulations On Silt Curtain Models
There is a lot of confusion and misunderstanding regarding silt curtain specifications and models, which is mainly due to the fact that there is no international body or organization responsible for setting standards or specifications. This has resulted in a proliferation of model codes and materials, which have the appearance of conforming to a specification, but are in no way related or comparable. There is a clear need for international regulations on silt curtain models.
It makes the buying decision incredibly difficult, as the purchaser or engineer is often not comparing a like-for-like product offering. This results in a pure price comparison rather than determining what specification is right for the environmental conditions, and can lead to performance issues on site, which can have a significant cost impact in terms of damages and delays.
There are generally three major regions that follow a form of model coding for silt curtains: USA, Asia and MENA. Other regions do exist, however, do not appear to follow any set coding system. Regardless of following similar coding or not, comparing model codes between these regions is not a useful exercise, as the physical properties of the silt curtains are very different.
|Model Codes||Type I, II, III or Type 1, 2, 3||Type I, II, III or
SC-100, SC-150, SC-200
|Type I, II, III, IV, V|
|International Body or Organization||Set at state level by the Department of Transport (DOT), which is why the curtains are referred to as ‘DOT’ specification. DOT is different in each of the 50 states. The specification for curtains differs in each state as well, providing basic guidelines that are not linked to the environmental conditions the curtains will be applied in. There is no set standard or minimum specification.||No governmental guidelines. It is at the discretion of the supplier.||MENA coding was first introduced by Ecocoast in 2012, as curtains were originally produced to USA DOT specifications. After applying and testing regionally, the specifications were quickly abandoned due to poor performance. Even though coding appears similar to USA coding, properties are different and not comparable. This coding has now been adopted by other MENA manufacturers.|
|Model Differences||The USA curtains are not
as strong as Asia and Gulf models. They usually use lightweight geotextile or PVC skirts that have a low tear strength, causing failures.
|The Asia curtains are stronger than USA models, but lack high strength anchor points, reinforced float pockets and may have non-continuous segmented floats.||Ecocoast developed a new iteration of silt curtains, using high tensile strength fabrics, reinforcements bands and heavy-duty anchor points. The curtains are stronger than USA and Asia models.|
Based on the above information, it is evident that comparison of curtains across different suppliers and regions by model codes cannot be reliably made. In absence of an international body setting minimum specifications based on the environmental conditions, care must be taken when selecting the appropriate silt curtain for site conditions. We are advocating the setting of clear regulations for silt curtain standards internationally.
Ecocoast recommends speaking to a specialist with proven experience of providing silt curtains for regional conditions and for recommendations to be supported by force calculations provided by the supplier based on environmental data from site, or engaging the services of a third party consultant to review the product submissions.
If you’re interested in knowing more, get in touch with us!