The amazing exploding NUS solar cell laboratory

from Channel NewsAsia

Barely a day after the National Day parade fireworks, the NUS put up its own pyrotechnics display when a laboratory in Engineering Block E3A blew up. The lab was apparently involved in the production of solar cells. Will we ever know the reason for this massive explosion which thankfully did not result in any serious injury or death? I don't think so, given our local tendency to hide everything. Pity, because there are lessons in it for all.

The link between the manufacture of solar cells and the explosion may not be readily apparent to the uninitiated, but actually solar cell manufacturing is extremely dangerous because it deals with highly explosive materials. Those within the industry will know that the easiest and cheapest way of bonding layers of silica to make the solar cells is through the use of a gas called silane. Silane is actually a combination of silica and hydrogen, and is a very capriciously flammable gas. In chemical terms, the gas is termed pyrophoric, which means it can readily burst into flames even without any sparks to trigger it off. This explosiveness is quite unpredictable and can occur after a delay in exposure.

Over the last few decades, many spectacular silane related explosions  (Bangalore, Taiwan, Osaka to mention a few)  have been reported which have killed a total of at least 20 people. That there was no loss of life at the NUS explosion was more a result of good fortune than good lab practice.

Truth is, silane is a very dangerous gas, whose capriciousness needs to be managed extremely carefully. One of the most dangerous places to use silane, in fact, is in small enclosed spaces - like university labs, or fume cupboards. I need to point out that I have no inside info about whether silane was involved in the NUS accident, but everything I have read points to it being the reason behind the explosion. If so, one wonders how approval was obtained to store and use silane in a relatively common area university laboratory where students come and go.

I really hope the results of lab accident investigations can be made public, the way flight accidents are, so that we all can learn from any mistakes made. But in Singapore, that may be too much to ask.

Recommended reading:
ANSI standards on how to store and handle silane - CGA G-13