Form
The MRP Modular Protection System is in the form of hollow interlocking blocks each block measuring 500 mm deep. The basic Wall and Corner blocks measure 1000 mm long by 750 mm high. Combinations of smaller blocks are available, designed to fit this same modular size. The weight of the largest block is 33 kg. The typical wall thickness is 18mm.
Each block is provided with interlocking features on all four edges, 2 male and 2 female, with lifting/ fixing holes in the main faces. A 50 mm hole is built into the top face of the block for the purposes of filling and emptying of the chosen material (water, sand, iron or lead shot or grout).

Materials of Construction
The blocks are manufactured in black polyethylene by the rotational moulding technique and are, therefore, devoid of any construction joints. The black polyethylene has less than 2% carbon black compounded into the base polymer, providing practically unlimited UV resistance and good radiation stability.
The blocks are manufactured in two stages. The first process provides a dense outer coating of polyethylene, then a second process includes a foaming agent, giving an expansion of up to 2.5 times, providing the inner coating. Both coatings cure simultaneously and so are bonded together. This results in a total wall thickness of approximately 18 mm with a good strength to weight ratio.

Accessories
There are a number of 'add-ons' that are available, if required. A variety of external polyethylene fixing plates and nylon setscrews, extract pumps, lifting grabs etc. are available. Also available are 'over the wall' structures for facilities where wind loadings and impacts must be considered. MRP provide a design advisory service to assist clients with their applications.

Decontamination
The surface finish of the blocks is polished and free from inclusions, resulting in a product which can be easily decontaminated, for re-use elsewhere. The use of strippable coatings is recommended where heavy airborne contamination is expected. The smooth surface of the block will aid the removal of the strippable coating when required. The smooth polyethylene finish can be easily wiped over to remove loose contamination and the potential for contamination traps have been minimised.

Traceability
Each block is marked with an adhesive, metallic backed, label with a discreet bar code number that is entered in the company held database. We are, therefore, able to provide a life history of every block supplied.