1 Breakages are less as the boards are much tougher and have fibers reinforcing in them. 2  they damage less easy from general wear and tear in everyday use in a home or office. 3  It offers slightly better acoustics than standard board.  It is a superior product in case of fire.
It is normal for the solenoid to make noise, it clicks when the valve is turned on or off. It also is normal for a very soft buzzing sound to be heard when the valve is activated, but you should not be able to hear it unless you put your ear near it. If you can easily hear it buzzing, that is not normal.
A carotid bruit is a systolic sound heard over the carotid artery area during auscultation. It may occur as the result of carotid artery stenosis (though some disagree); however, most carotid bruits, particularly those found in younger or asymptomatic patients, are not related to any disease and are termed innocent carotid bruits.