Abstract: A thief hatch state monitoring system includes a thief hatch sensor that detects a change in angular position of a thief hatch and generates sensor data at an output in response to the detected change. A processor having an electrical input is electrically connected to the output of the thief hatch state sensor. The processor determines when the angular position of the thief hatch changes by more than a predetermined amount from the sensor data and then generates a transmit signal indicating a state of the thief hatch. A network interface is electrically connected to an output of the processor. The network interface generates a signal that indicates the state of the thief hatch. A communication gateway includes a receiver that receives the signal indicating the state of the thief hatch. The communication gateway is electrically connected to a network that provides an end-user remote access to the state of the thief hatch.

Abstract: An emergency lighting system includes a plurality of emergency lights and a plurality of emergency power systems. Each of the plurality of emergency power systems is electrically connected to a respective one of the plurality of emergency lights through a respective one of a plurality of power switches. The emergency lighting system also includes a plurality of processors. Each of the plurality of processors is electrically connected to a respective one of the plurality of emergency power systems and executes software that monitors a status of a respective one of the emergency power systems and controls a state of the plurality of power switches. The emergency lighting system also includes a plurality of radio transceivers. Each of the plurality of radio transceivers is electrically connected to a respective one of the plurality of processors and communicates with other radio transceivers in the plurality of radio transceivers that are in radio wave proximity.

Abstract: An emergency lighting system includes a plurality of emergency lights and a plurality of emergency power systems. Each of the plurality of emergency power systems is electrically connected to a respective one of the plurality of emergency lights through a respective one of a plurality of power switches. The emergency lighting system also includes a plurality of processors. Each of the plurality of processors is electrically connected to a respective one of the plurality of emergency power systems and executes software that monitors a status of a respective one of the emergency power systems and controls a state of the plurality of power switches. The emergency lighting system also includes a plurality of radio transceivers. Each of the plurality of radio transceivers is electrically connected to a respective one of the plurality of processors and communicates with other radio transceivers in the plurality of radio transceivers that are in radio wave proximity.

Abstract: Truss arrangements utilizable in ladder sections of extendible ladder arrangements are described. Also described are ladder arrangements utilizing in the truss arrangements, and methods designed in use.

Abstract: An emergency lighting system includes a plurality of emergency lights and a plurality of emergency power systems. Each of the plurality of emergency power systems is electrically connected to a respective one of the plurality of emergency lights through a respective one of a plurality of power switches. The emergency lighting system also includes a plurality of processors. Each of the plurality of processors is electrically connected to a respective one of the plurality of emergency power systems and executes software that monitors a status of a respective one of the emergency power systems and controls a state of the plurality of power switches. The emergency lighting system also includes a plurality of radio transceivers. Each of the plurality of radio transceivers is electrically connected to a respective one of the plurality of processors and communicates with other radio transceivers in the plurality of radio transceivers that are in radio wave proximity.