Fire resistant lining system

Field of the Invention

The present invention relates to the containment of hazardous liquids. In a preferred embodiment of the invention, the invention relates to the containment of liquids which may leak/spill from a primary containment reservoir.

Background Art

Where large volumes of liquid are required to be stored, tanks or large vessels are constructed and the liquid is contained therein. These liquids are often flammable and may also be toxic. It is therefore highly desirable that in the event of a tank rupture, the liquid is contained within a secondary containment area.

Currently, this secondary containment area requires a barrier, such as an earthen wall or bund to be constructed around the tank. The size and location of the bund is such that the liquid, if discharged from the tank can be contained within the area.

Obviously once a liquid has been discharged the earth bund will absorb and allow the liquid to leach therethrough. To prevent this from happening the bund is covered in concrete, asphalt or high density polyurethane (HDPE), all of which have varying fire retardation properties. These products are unfortunately not without problems.

• Asphalt is prone to cracking, degrades over time and is not resistant to petroleum based products.

• Concrete by its very nature is also prone to cracks, expands and contracts in varying climatic conditions.

• A HDPE system typically consists of a 1.5mm HDPE sheet membrane, welded on site and commonly used to line dams. The HDPE membrane is not fire resistant, and is prone to expansion and buckling in the

presence of sunlight. Furthermore, in some applications, the HDPE membrane is retained in place along its bottom edge using a weight such as gravel. This prevents the membrane from being visually inspected. Hence, upon visual inspection the integrity of the membrane cannot be ascertained in those areas. Furthermore, as the membrane is relatively thin it does not have high wear properties and is not tolerant to traffic.

The preceding discussion of the background to the invention is intended only to facilitate an understanding of the present invention. It should be appreciated that the discussion is not an acknowledgement or admission that any of the material referred to was part of the common general knowledge as at the priority date of the application.

It is an object of this invention to provide a lining system which is fire resistant and can contain fluid within the designated catchment area.

SUMMARY OF INVENTION

The present invention provides a lining system to line a surface of a containment area, the lining system comprising:

a first layer comprising a first material having fire resistant properties, the first layer having been sprayed onto the surface,

a second layer being of a second material, the second material being flexible and capable of preventing a flame passing therethrough;

a third layer comprising a third material sprayed onto the second layer.

Preferably the third layer bonds to the second layer.

Preferably one or both of the first and third layers are formed from a polyurea having fire resistant properties.

Preferably one or both of the first and third layers are formed from a polyurea having anti-static properties.

The compounds which provide the layer with fire resistant and/or antistatic properties are incorporated in the material at the time the material is spray applied.

Preferably the first and third layers are the same material and may be flexible. Preferably the polyurea is self extinguishing. The polyurea may have high wear resistant properties.

Preferably the first layer is 2 to 5 mm in thickness. Preferably the third layer is 2 to 5 mm in thickness.

Preferably the second layer has minimal absorption properties. Whilst the material may allow an acceptable level of liquid to pass therethrough the material does not absorb the liquid. Preferably the second layer provides protection to the first layer in the event the third layer is compromised. Should this happen the first layer may stop fluid from passing outside the containment area.

Preferably the second material is a woven fiberglass fabric. The fabric may be coated with an aluminum polymer which provides a heat reflecting surface. Preferably the second material is known as Firescreen FC455P2.

In one aspect of the invention the first layer is applied to concrete. This may be the case when applying the current invention to a containment area previously lined with concrete.

In another aspect of the invention a layer of geotextile material is applied to the surface of the containment area before the first layer is applied thereto.

As the first and third layer are applied using a spray system, the liner is seamless. Furthermore the polyurea has a high wear resistant and is therefore tolerant to traffic.

Owing to the construction of the liner, damaged sections are easily replaced.

Preferably the second layer terminates a distance from the periphery of the first layer, allowing the third layer and first layer to bond together around the periphery of the second layer, effectively encapsulating the second layer within the first and third layers.

Where the periphery of the liner meets the primary containment area (i.e. the tank base) a primer may first be applied to the surface before the first layer is applied, assisting in the bonding of the liner to the surface.

The primer may be applied to the surface before the geotextile is laid.

Preferably the third layer remains flexible and intact after it has been burnt.

The liner prevents the liquid from passing into the subsoil, and ensures the liquid is contained in the event of a fire.

Preferably the third layer is UV stable and chemical resistant.

Preferably the first layer is UV stable and chemical resistant.

The present invention also provides a lining system to line a surface of a containment area, the lining system comprising:

a first layer sprayed onto the surface and comprising a first material,

a second layer being of a second material, the second material being flexible and capable of preventing a flame passing therethrough;

a third layer comprising a third material sprayed onto the second material, bonding thereto, the third layer having fire resistant and anti static properties.

The lining system may also be applied to structural beams, used as a fire rated curtain wall, fire doors, etc.

The present invention also provides a method of lining a containment area comprising the following steps:

spraying a first layer of a first material onto a surface of the containment area;

applying a second layer to the first layer, the second layer being a woven, flexible, fire resistant material; and

spraying a third layer of a third material onto the second layer, the third material being fire resistant.

The method may further comprise the step of clearing the site before installing the lining system.

The method may further comprise the step of laying a geotextile over the surface of the containment area prior to applying the first layer.

The present invention also provides a lining system which can be applied to a structure such as structural beams or fire doors, the lining system comprises:

a fire proof layer secured to the structure;

a layer of fire resistant and antistatic material sprayed on the fire proof layer so as to be adhere thereto.

Description of the Drawings

The invention will be better understood by reference to the following description of several specific embodiments thereof as shown in the accompanying drawings in which:

Figure 1 and 2 are photographs of a lining system according to the prior art;

Figure 3 is a schematic cross sectional view of a lining system according to an embodiment of this invention;

Figure 4 is a view of the lining system of figure 3 schematically shown in position according to an embodiment of the invention.

Best Mode(s) for Carrying out the Invention

Referring to figures 1 and 2, the lining system illustrated utilises HDPE sheet membrane 11 in position around a storage tank 13 to provide a lined secondary containment region, known as a storage bund 15. As can be seen in these figures, the storage bund 15 incorporates a perimeter wall 17 around the storage tank 13.

A lining system 19 according to the first embodiment is shown in figure 3 with an application of the system 19 shown in figure 4.

Referring to figure 3 the lining system 19 comprises a first layer 21. The first layer 21 is sprayed onto a layer of geotextile material 23 which has been laid on a substrate 25, and buried along its edge, as shown in figure 4. The first layer is a polyurea fire resistant elastomer, which once cured, provides a flexible barrier to liquid and fire. As the first layer 21 is sprayed on to the geotextile 23 there is no joins or seams therein.

Once the first layer 21 has been sprayed, a second layer 27 is positioned thereon. The second layer 27 comprises a flexible woven fiberglass mesh having fire retardant properties. The second material is substantially non- absorbent, allowing a small amount of liquid to pass therethrough whilst preventing any flame from passing through the material.

Once the second layer 27 is in place, a third layer 29 is sprayed onto the second layer 27. The third layer comprises the same material as that used for the first layer 21 with the addition of further components to provide the third layer 29 with anti static characteristics. The third layer 29 provides the first line of defense to any flame or liquid which may be spilt in the storage bund 15. Again, as the first third layer 29 is sprayed applied there is no joins or seams therein.

When installing the lining system 19, the second layer 27 may terminate a distance from the peripheral edge 31 of the first layer 21 as shown in figure 4. When the third layer 29 is applied the third layer is sprayed up to the peripheral edge 31 , encapsulating the second layer 27 therebetween.

The third layer 29 also protects the second layer 27 from the weather, which, overtime, would reduce the effectiveness of the second layer 27 in preventing fire passing therethrough.

In the embodiment shown in figure 4, the second layer 27 is only positioned on the sides of the storage bund 15 and under any equipment 33 from which liquid may spill.

As is known to the person skilled in the art the lining system or a layer thereof extends beyond the top 35 of the storage bund and is typically secured in a trench 37.

A bonding primer (not shown) may be first applied to ensure the first layer 21 bonds to the substrate. This may be particularly critical where the lining system 19 engages the storage tank 13.

Owing to the configuration of the lining system, it is easy to replace a small damaged portion of the lining system as opposed to having to replace the whole system to obtain a secure system. Should however the fire be substantial, the second layer may simply be folded and removed taking the third layer with it. A new second layer may then be laid and a new third layer sprayed thereon.

Modifications and variations such as would be apparent to the skilled addressee are considered to fall within the scope of the present invention.

Throughout the specification, unless the context requires otherwise, the word "comprise" or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.