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Silt curtain specifications
Published on 25 Sep ‘24
Silt Curtain Specifications and Types: What You Need to Know
Silt curtain specifications and types

When it comes to silt curtains, the specifications and types can be confusing. This is because there is no international standard for silt curtains, leading to many different codes and materials used across regions.

In this blogpost, we will break down some of the key regional differences to help you better understand silt curtain specifications. Let’s take a closer look at 3 of the major regions that have their own distinct fabrication methods and a form of alignment in product coding: the USA, Asia and the Gulf. This is not to say there are not more regions and sub-regions – Europe and Australasia are both distinct regions and both have very different models of silt curtains. However, there is generally less alignment among suppliers with the coding used.

ASIA, USA AND GULF SILT CURTAIN TYPES COMPARED

Silt curtains in Asia

In Asia, the model codes for silt curtains vary widely. They historically tended to follow the format SC-xxx (eg. SC-100, SC-150, SC-200). These numbers refer to the strength of the curtain’s fabric, measured in kiloNewtons (kN).

However, these codes only tell you about the skirt strength, and not about other important factors like float size, float type, tension elements, anchoring connections or environmental conditions.

💡 Key takeaway: These curtains are often used offshore and have high tensile strength fabrics, but they might lack features like reinforced float pockets or high strength anchor points.

Turbidity curtains in the USA

In the USA, silt curtains are known as turbidity curtains. Their model codes tend to follow a Type x format (eg. Type I, Type II, Type III or Type 1, Type 2, Type 3). These codes are based on specifications set state-level by U.S. Department of Transportation (DOT).

However, the DOT guidelines are inconsistent across states and typically offer only basic information, such as minimum float size or skirt strength, without considering the environmental conditions in which the curtains will be used.

💡 Key takeaway: USA turbidity curtains are often used in sheltered waters and tend to be made from lightweight geotextile or PVC skirts. These curtains are not as strong as those used in Asia or the Gulf. They are also used much more frequently in calm water, rivers or waterways where they may not need to be built to the same offshore standards.

Silt curtains in the Gulf

In the Gulf region, silt curtains also follow a Type x model code (eg. Type I, Type II, Type III, Type IV). At first glance, these codes look similar to the USA system, but the curtains themselves are much stronger and could not be more different.

Ecocoast was the first to introduce the Type I, II, III, IV coding to the Gulf region. In 2011, silt curtains used to be produced to meet USA DOT specifications.

However, after testing them in Gulf waters, we quickly learned that what works in waterways, does not necessarily work in more exposed conditions where the majority of installations are (given a distinct lack of waterways in the region). The wire tension cables and PVC skirts did not perform well in exposed conditions, so we fully adapted them, using high-tensile fabrics, reinforcement bands and heavy-duty anchor points.

Lately there has also been some divergence within the Type I, II, III and IV specifications further causing confusion. What used to be a homogeneous design, is now fragmenting into minor design variations with words like “Gulf Spec” or “Heavy Duty” being appended to the end of the Type specification in order to provide variability within a Type. This is a largely market-driven phenomenon that occurs due to a lack of standardisation or regulation. It comes from increased demand and increased competition, with each producer vying to offer something slightly different.

💡 Key takeaway: Gulf curtains are designed to withstand tougher environmental conditions, with stronger materials than their USA counterparts. Care needs to be taken in the future that the proliferation of models and codes does not further confuse customers. Customers will need to look beyond the model codes and datasheets to truly understand what they are purchasing.

Summary

AsiaUSAGulf
Model codeSC-100, SC-150, SC-200Type I, II, III or Type 1, 2, 3Type I, II, III, IV
International bodyNo governmental guidelines. It is at the discretion of the supplier.Set at state level by DOT, which is why the curtains are referred to as ‘DOT’ specification. DOT is different in all states. The specification for silt 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.Gulf coding was first introduced by Ecocoast, as curtains were originally produced to USA DOT specifications. After applying and testing regionally, the USA DOT specifications were quickly abandoned due to poor performance. Even though Gulf coding appears similar to USA coding, properties are different and not comparable. This coding has now been adopted by other MENA manufacturers.
FeaturesThe Asia silt curtains are stronger than USA models, but lack high strength anchor points, reinforced float pockets and may have non-continuous segmented floats.The USA silt 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.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.

What does all of this mean for you?

It is clear that comparing silt curtains from different regions just by looking at their model codes is not reliable. The environmental conditions in your area play a big role in choosing the right curtain. That is why it is essential to speak with a marine specialist who can recommend the best solution based on local conditions.

Download our guide

To help you make an informed decision, we created a guide that covers everything you need to know about selecting the right silt curtain model and anchoring system. Ensure your project is set up for success from the start!

Access the guide HERE.

At Ecocoast, we always recommend making sure your supplier provides detailed force calculations based on environmental data from your site. If you wish to receive further information, feel free to reach out to us.

📷 Top photos: Ecobarrier Silt Curtains ESC-150-2, pond soil accumulation and attenuation project, Belgium.

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