With the masters of Eliot and Adams Houses officially on-board, all 12 Houses will operate under universal keycard access between the hours of 8 a.m. and 1 a.m., come spring semester.

Last Wednesday, during one of their regular all-masters meetings, the masters of 10 Houses agreed to initiate a trial period of universal access.

But when the consensus was reached, Eliot and Adams House masters were not present.

When informed of the plan the next day, the two House's masters assented to the trial.

The policies of Eliot House will change the most, since it is the only House to not offer any universal keycard access at all.

Stephen Mitchell, an Eliot House co-master, said he had originally been concerned that keycard access would compromise security.

But now, the discussions over the past several years and successful trials in Quincy and other Houses have convinced him that universal access won't jeopardize safety, he said.

"I gather the College is no longer concerned about the 'two locked doors' issue...that has been our main worry historically," Mitchell wrote in an e-mail to several students last month as the change was being discussed.