
239 S.E.2d 847 (1978)
Donald SEARSEY (Employee),
v.
PERRY M. ALEXANDER CONSTRUCTION CO. (Employer), and Aetna Casualty & Surety Co. (Carrier).
No. 7728IC106.
Court of Appeals of North Carolina.
January 17, 1978.
*849 Gudger, McLean, Leake, Talman & Stevenson by A. E. Leake, Marshall, for plaintiff-appellee.
Uzzell & Dumont by J. William Russell, Asheville, for defendant-appellants.
CLARK, Judge.
Defendants attack the Commissioner's award as invalid because the plaintiff's injury was caused not by an accident but by an expected, foreseen event which was part of plaintiff's usual work. G.S. 97-2(6) of the Workmen's Compensation Act limits compensation to recovery for ". . . injury by accident arising out of and in the course of the employment, and shall not include a disease in any form, except where it results naturally and unavoidably from the accident." [Emphasis added.]
An "accident" is an unlooked for and untoward event not expected or designed by the employee. Harding v. Thomas & Howard Co., 256 N.C. 427, 124 S.E.2d 109 (1962). An "accident" is not established by the mere fact of injury but is to be considered as a separate event preceding and causing the injury. Beamon v. Grocery, 27 N.C. App. 553, 219 S.E.2d 508 (1975); Bigelow v. Tire Sales Co., 12 N.C.App. 220, 182 S.E.2d 856 (1971). No matter how great the injury, if it is caused by an event that involves both an employee's normal work routine and normal working conditions it will not be considered to have been caused by accident. 8 Strong's N.C. Index, 3d ed., Master & Servant, § 55.1, p. 534; Pardue v. Tire Co., 260 N.C. 413, 132 S.E.2d 747 (1963); Pulley v. Association, 30 N.C.App. 94, 226 S.E.2d 227 (1976). In the case sub judice, the Deputy Commissioner found:
"In the normal operation of an air hammer, there is some material under the pavement which is being broken which allows the operator of the air hammer to draw it back slowly. It is unusual, in the operation of the air hammer,although not unnaturalfor the air hammer to jerk the operator when it breaks through the pavement." [Emphasis added.]
Her finding that the sudden breakthrough was unusual and not part of plaintiff's normal work routine and normal working conditions was amply supported by the evidence. The employee's use of the air hammer was usual in the sense that he regularly, though not often, used the tool in breaking concrete. Most of the time he used it to break concrete over soil or other supporting material. But at the time of the injury he was engaged in using the air hammer to break a concrete cap, reinforced for strength with steel, over (air) a well, which operation he did rarely. The drill of the hammer is driven downward by compressed air, aided by the weight of the hammer. The rate of penetration by the drill into the reinforced concrete is variable because the reinforcing steel will slow, if not stop temporarily, the penetration. The intermittent driving force of the compressed air gives the hammer a bucking or jerking action. Under these circumstances it was obviously difficult for the employee to determine the moment when the hammer would break through the concrete so that he could protect himself by lifting the hammer to minimize the sudden downward driving force. Under these circumstances, the sudden breakthrough of the air hammer was not expected or designed by the employee.
Defendants further contend that plaintiff's obvious knowledge of the risk involved in operating the hammer over air coupled with his knowledge that he was operating over air when he was hurt defeat his claim. We have stated earlier that an accident cannot be expected or designed. It is clear that these qualifications operate narrowly to exclude intentional injurious *850 acts. Petty v. Transport, Inc., 276 N.C. 417, 173 S.E.2d 321 (1970). Knowledge of risk ignored such as constitutes negligence is not grounds for denial of compensation. Hicks v. Guilford County, 267 N.C. 364, 148 S.E.2d 240 (1966). To withhold compensation from a non-negligent employee because he knew the risks of his work, even though that work was unusual to him, would defeat the purpose of Workmen's Compensation. An employee must be compensated for such injury when he is required to do a piece of work and has no choice but to do it as best he can. We are mandated to construe the Workmen's Compensation Act as liberally as possible so as not to deny benefits on technical, narrow and strict grounds. Cates v. Construction Co., 267 N.C. 560, 148 S.E.2d 604 (1966). Plaintiff's knowledge of the risks of operating an air hammer over air did not make his "unusual" task usual; it did not make even a probable injury "expected." The evidence demonstrated that even an experienced operator over air could not know precisely when the hammer would break through.
The Deputy Commissioner's finding that the event of sudden breakthrough which injured the plaintiff was unusual was amply supported by the evidence and justified her conclusion that the event was an accident. The order of the Full Commission adopting the opinion and award of the Deputy Commissioner is
Affirmed.
BROCK, C. J., and MARTIN, J., concur.
