BUILDING for PROTECTION in MERAPI?

The eruption of Mount Merapi, 5 November 2010 had resulted many casualties which were generally caused by heat clouds "wedhus gembel." People's houses could no longer serve as a protector and mostly destroyed by the blast of hot clouds that supposedly reach speeds of up to 300km/hr. In addition to its high speed, hot clouds can reach temperature around 600 degrees Celsius. The threat was also come from hot material heap too often among the houses located near the peak of Merapi.

Till now, the only way considered as the most appropriate to survive the wrath of the hot cloud is of course to avoid it. No any single organism that can survive at that very high temperature even for short periods. In the 2006 eruption, even custom-made bunkers for protection against hazards for Merapi still killed two volunteers who were trapped in it. So in theory, the protection of buildings against heat clouds and avalanches of material is difficult.

However, it does not mean that nothing can be done related to the protection around this volcano hazards. To run away is the first choice that must be done, but for those who do not have chance, to find protection in order to survive is the only way. This protection can only offered by buildings.

There are three main aspects to be considered for designing the protector building around the Merapi namely; strong winds, high temperatures, and the burden of volcanic material. To avoid those three things, the simplest strategy, but it is not easy to do, is to create a kind of foxhole "bunker" beneath the ground. Bunker is relatively safe from hot clouds attack that occurs in a short time. The deadly bunker case in 2006 that took lives is because the bunker was directly covered very hot material in a long time, so the room be turned into an 'oven' for the victims in it.

The second alternative is to build strong buildings withstand winds, temperature and heavy loads. In this case, the entirely reinforced concrete construction of the wall and roof is the most appropriate. Concrete will able to anticipate great loads from material on it, blowing wind and high temperatures. In terms of ability to withstand radiation or convection heat, concrete is better than other building materials due to high thermal lag. Wood and metal are not recommended since the material is easy to conduct heat and cannot stand in high temperatures.

This building protection is needed for any community groups, or even in every home residents if possible. The first and second alternative above would be expensive and not economical, but nevertheless it does not mean cannot be implemented. Abundant sand resources are one benefit that has been provided by the nature of Merapi. Nature seems to provide its own solution, abundant and good quality of sands is well known as one answer to the most appropriate materials should be used in such region. Besides, reinforced concrete construction is not new for people around Merapi. Moreover, the price of a safety would be more than anything.

And what about houses? We discuss later ...