Personal safety is always of utmost importance, here are a few comments on this topic:
 
Before venturing out on to a rooftop it is important to be aware that the temperature of a roof's surface may be as much as 60 - 70 Degrees higher than the ambient temperature. Dehydration can set in quickly under these conditions. During days of excessive heat, rooftop visits should be limited to brief time increments. Any personnel that must be out on the roof should be well prepared including proper protective clothing and plenty of drinking water.
 
Dehydration does not only effect workers on the roof; but can also be a threat to those performing other outdoor tasks. When performing work from a suspended scaffold, regularly scheduled breaks should be allocated to allow workers time to cool off in the shade and replenish fluids. An ample supply of water or sports drinks should be provided to workers on suspended scaffolds as it is not easy for them to get water from the job site water cooler as needed.
 
With the heat of summer we also often have fast moving thunderstorms; therefore weather forecasts should be monitored regularly. Thunderstorms often bring wind and lightning which can be of great risk to personnel on the exterior of a building. In addition to suspending work activities prior to the onset of thunderstorms all loose material should be secured from wind uplift. Lightweight insulation boards should be of particular concern.

Many buildings, particularly older residential buildings, require the use of window mounted air conditioners to cool interior spaces in the summer months. These units must be installed properly using brackets approved for use with the individual unit. At a minimum improperly installed air conditioners may damage the window frame; however the greater risk is posed by a unit falling from a window. In New York City improperly installed window air conditioning units are considered unsafe conditions under the guidelines of LOCAL LAW 11\98 and must be reported as such to the Dept. of Buildings. To avoid any unnecessary risks a comprehensive A\C unit installation and\or inspection plan should commence at the start of the summer.

If any exterior restoration is to be performed in the vicinity of air conditioning intakes, properly designed filters should be installed and replaced regularly throughout the duration of the work
 
Another issue that effects many residential buildings in the summer is the increased use of balconies and terraces. As we are all aware a tragedy recently occurred in New York City involving a failed balcony railing. With the combination of the degrading effects that the harsh winter weather has on railing connections, posts, balusters and infills and the increased stresses applied to railings in the summer; proper inspections of railings and connections should be performed at the start of every summer.
 
Many materials used in building envelope restoration are negatively effected by extreme heat., including mortar, sealants, paints, coatings and  roofing & waterproofing adhesives. Particular attention should be paid to the manufacturer's and the engineer's requirements for temperature restrictions on the installation of these materials. It is not only the temperature at the time of installation, but the anticipated temperature during the curing time of these materials that is of concern.