The EC 50-6 Triple allows a community to be grown one module at a time. The first EC 50-6 is installed with two tunnels that are capped off. To add the second EC 50-6 or EC 50-10 or larger Earthcom requires excavation only down to the 45 degree tunnel without having to unearth the spiral stairwell. Each EC 50 shelter has a secondary exit. See the EC 50-6 for specifications.